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Electric-field effects and interactions of dye-polymer systems

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Title:
Electric-field effects and interactions of dye-polymer systems
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Book
Language:
English
Creator:
Hilker, Brent
Publisher:
University of South Florida
Place of Publication:
Tampa, Fla
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Subjects

Subjects / Keywords:
MALDI-TOF
Dielectric Analysis (DEA)
Induction Based Fluidics (IBF)
Poly(methyl methacrylate) (PMMA)
Electric Modulus
Dissertations, Academic -- Chemistry -- Masters -- USF   ( lcsh )
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non-fiction   ( marcgt )

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Abstract:
ABSTRACT: Matrix Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) mass spectroscopy is used in the characterization of synthetic polymers. MALDI allows for determination of: modal, most probable peak (Mp), molecular number average (MN), molecular weight average (Mw), polydispersity (PD), and polymer spread (Psp). We evaluate a new sample preparation method using Induction Based Fluidics (IBF) to kinetically launch and direct nanoliter volumes to a target without contact. IBF offers signal improvement via field enhanced crystallization. This is the first study to discuss filed enhanced crystallization in MALDI sample preparation. IBF can increase signal/noise (S/N) and signal intensity for polystyrene (PS), poly(methyl methacrylate) (PMMA), and poly(ethylene glycol) (PEG) across a mass range of 2,500 to 92,000 Da showing more accurate PSP. Increases in S/N range up to: 279% for PS, 140% for PMMA, and 660% for PEG. Signal intensities increased up to: 438% for PS, 115% for PMMA, and 166% for PEG. Cross-polarization microscopy indicates dramatic morphology differences between IBF and micropipette. Finally, we speculate as to why IBF nanoliter depositions afford higher S/N values in experiments conducted in different instrumental configurations even without optimization. Next we sought to investigate whether nanoliter volumes of concentrated polar liquids and organic monomers launched to targets using IBF can be verified through the real time charge measurements. We show that using a nanoliter IBF dispensing device and nanocoulomb meter, charge measurements made on nanoliter drops in real time are correlated with the droplets surface area following Gauss's Law. We infer the "induction only" formation of the double layer showing the ability to determine nanoliter volumes, nearly instantaneously, in real time. Implications are presented from these IBF measurement observations on improving/monitoring MALDI quantitation and its quality control. Polymer-dye interactions were further investigated using PMMA composites made from a polar metalloporphyrin 5-(4',4',5',5'-tetramethyl1',3',2'dioxaborolan-2'-yl)-10,20-diphenylporphyrinatozinc(II) (Zn(II)Bpin-DPP) in select weight %s (wt%s). Fluorescence spectroscopy has revealed that the porphyrin was well dispersed within the composite. Differential Scanning Calorimetry (DSC) showed that porphyrin acted as an antiplasticizer raising the glass transition (Tg) from 105 °C to 123 °C. Dielectric Analysis (DEA) was performed in the frequency range of 0.3 Hz to 100 kHz between -150 to 270 ⁰C. Permittivity (ε'), loss factor (ε'') and dielectric response of beta (β), alpha beta (αβ), and conductivity relaxations were studied. Previous DEA data was limited to 190 ⁰C. This study brings analysis to 270 ⁰C which is start point for the first part of PMMA degradation. Thus forwarding DEA can be used to evaluate PMMA degradation. The electric modulus formalism is used to reveal the β and conductivity relaxations. The apparent activation energies (Ea) for the molecular relaxations are presented. AC (σAC) and DC (σDC) conductivity are also evaluated. Tan delta (δ), dissipation factor, evaluated between 1 Hz to 100 kHz was shown to increase with porphyrin loading although locally affected by free volume restriction. Havriliak-Negami (H-N) equation was fit using the complex electric modulus (M*) modified form and was performed on the conductivity region 160 to 190 ⁰C and degradation region 190 to 270 °C. Relaxations above the Tg were proven to be conductivity relaxations using four proofs. This is the first study to investigate PMMA degradation DEA with the complex electric modulus, M*, revealing a unique occurrence of increasing central relaxation times (1/s) and reducing electric loss modulus (M") frequency maxima (Hz) after the degradation temperature of 220 ⁰C was reached supporting current literature of the first of a two part degradation process that proceeds via end chain scission.
Thesis:
Dissertation (PHD)--University of South Florida, 2010.
Bibliography:
Includes bibliographical references.
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Mode of access: World Wide Web.
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System requirements: World Wide Web browser and PDF reader.
Statement of Responsibility:
by Brent Hilker.
General Note:
Title from PDF of title page.
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Document formatted into pages; contains X pages.

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usfldc doi - E14-SFE0004703
usfldc handle - e14.4703
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ABSTRACT: Matrix Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) mass spectroscopy is used in the characterization of synthetic polymers. MALDI allows for determination of: modal, most probable peak (Mp), molecular number average (MN), molecular weight average (Mw), polydispersity (PD), and polymer spread (Psp). We evaluate a new sample preparation method using Induction Based Fluidics (IBF) to kinetically launch and direct nanoliter volumes to a target without contact. IBF offers signal improvement via field enhanced crystallization. This is the first study to discuss filed enhanced crystallization in MALDI sample preparation. IBF can increase signal/noise (S/N) and signal intensity for polystyrene (PS), poly(methyl methacrylate) (PMMA), and poly(ethylene glycol) (PEG) across a mass range of 2,500 to 92,000 Da showing more accurate PSP. Increases in S/N range up to: 279% for PS, 140% for PMMA, and 660% for PEG. Signal intensities increased up to: 438% for PS, 115% for PMMA, and 166% for PEG. Cross-polarization microscopy indicates dramatic morphology differences between IBF and micropipette. Finally, we speculate as to why IBF nanoliter depositions afford higher S/N values in experiments conducted in different instrumental configurations even without optimization. Next we sought to investigate whether nanoliter volumes of concentrated polar liquids and organic monomers launched to targets using IBF can be verified through the real time charge measurements. We show that using a nanoliter IBF dispensing device and nanocoulomb meter, charge measurements made on nanoliter drops in real time are correlated with the droplets surface area following Gauss's Law. We infer the "induction only" formation of the double layer showing the ability to determine nanoliter volumes, nearly instantaneously, in real time. Implications are presented from these IBF measurement observations on improving/monitoring MALDI quantitation and its quality control. Polymer-dye interactions were further investigated using PMMA composites made from a polar metalloporphyrin [5-(4',4',5',5'-tetramethyl[1',3',2']dioxaborolan-2'-yl)-10,20-diphenylporphyrinato]zinc(II) (Zn(II)Bpin-DPP) in select weight %s (wt%s). Fluorescence spectroscopy has revealed that the porphyrin was well dispersed within the composite. Differential Scanning Calorimetry (DSC) showed that porphyrin acted as an antiplasticizer raising the glass transition (Tg) from 105 C to 123 C. Dielectric Analysis (DEA) was performed in the frequency range of 0.3 Hz to 100 kHz between -150 to 270 ⁰C. Permittivity (ε'), loss factor (ε'') and dielectric response of beta (β), alpha beta (αβ), and conductivity relaxations were studied. Previous DEA data was limited to 190 ⁰C. This study brings analysis to 270 ⁰C which is start point for the first part of PMMA degradation. Thus forwarding DEA can be used to evaluate PMMA degradation. The electric modulus formalism is used to reveal the β and conductivity relaxations. The apparent activation energies (Ea) for the molecular relaxations are presented. AC (σAC) and DC (σDC) conductivity are also evaluated. Tan delta (δ), dissipation factor, evaluated between 1 Hz to 100 kHz was shown to increase with porphyrin loading although locally affected by free volume restriction. Havriliak-Negami (H-N) equation was fit using the complex electric modulus (M*) modified form and was performed on the conductivity region 160 to 190 ⁰C and degradation region 190 to 270 C. Relaxations above the Tg were proven to be conductivity relaxations using four proofs. This is the first study to investigate PMMA degradation DEA with the complex electric modulus, M*, revealing a unique occurrence of increasing central relaxation times (1/s) and reducing electric loss modulus (M") frequency maxima (Hz) after the degradation temperature of 220 ⁰C was reached supporting current literature of the first of a two part degradation process that proceeds via end chain scission.
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Advisor: Julie P. Harmon, Ph.D.
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Dielectric Analysis (DEA)
Induction Based Fluidics (IBF)
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Electric Modulus
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Electric Field Effects and Interactions of Dye Polymer S ystems By Brent Hilker A dissertation submitted in partial fulfillment o f the requirements for the degree of Doctor of Philosophy Department of Chemistry College of Arts and Sciences University of South Florida Co Major Professor: Julie P. Harmon, Ph.D. Co Major Professor Abdul Malik, Ph.D. Mark L. McLaughlin, Ph.D. Xaio Li, Ph.D. Nathan Crane, Ph.D. Date of Approval October 20, 2010 Keywords: MALDI TOF, Dielectric Analysis (DEA), Induction Based Fluidics (IBF), Poly(methyl methacrylate) (PMMA), Electric Modulus Copyright 2010, Brent Hilker

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DEDICATION E vents have shaped my life to place Honor, Courage, and Commitment to the forefront of my being, and again I implore all to live by such a creed. I take this small section to pay my respect to all who have served the United States of America keeping her safe to make my life and pursuit of the American dream possible. Leadership and work ethics are taught not hereditary, and in being taught one can make their own path on merit. To a certain degree you make your own luck through h ard work. These life lessons have conferred upon myself the motivation needed to complete my goals and the fortitude to stand after failure. as I venture out to the land of experience. 1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is probably wrong. 2. The only way of discovering the limits of the possible is to ven ture a little way past them into the impossible. 3. Any sufficiently advanced technology is indistinguishable from magic Therefore it is with great pride that I dedicate this manuscript to my parents Patricia and Otto Aliffi, my Father who has passed Fred Hilker, and my future wife Joyie Lamz. They have been my inspiration and foundation in my life.

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i TABLE OF CONTENTS LIST OF TABLES ................................ ................................ ................................ ........... i v LIST OF FIGURES ................................ ................................ ................................ ........ v i i LIST OF EQUATIONS ................................ ................................ ................................ ... xi LIST OF SYMBOLS AND ABBREVIATIONS ................................ ................................ x i ii ABSTRACT ................................ ................................ ................................ .................. x v i i CH APTER 1 : E LECTRIC F IELD E NHANCED S AMPLE P REPARATION FOR S YNTHETIC POLYMER MALDI TOF M ASS S PECTROMETRY VIA INDUCTION BASED FLUIDICS (IBF) ................................ ................................ ........... 1 1.1 Introduction ................................ ................................ ................................ .... 1 1.2 Experimental ................................ ................................ ................................ .. 9 1.2.1 MALDI Reagents ................................ ................................ ............. 9 1.2.2 Sample Recipes and Preparation ................................ .................. 10 1.2.3 MALDI TOF MS Calibration ................................ ........................... 11 1.2.4 MALDI Sampling Method & Data Analysis ................................ ..... 12 1.2.5 Nanoliter Induc tion Based Fluidic (IBF) Device .............................. 12 1.2.6 Cross Polarization Microscopy ................................ ....................... 1 3 1.3 Results and Discussion ................................ ................................ ................ 1 3 1.3.1 Polystyrene ................................ ................................ .................... 1 4 1.3.1.1 PS (2300 Da), RA, AgTFA: (PS 2 RA) ............................ 1 4 1.3.1.2 PS (2300 Da), TPB, AgTFA (PS 2) ................................ 1 8 1.3.1.3 PS (6000 Da), TPB, AgTFA: (PS 6) ................................ 2 1 1.3.1.4 PS (92,600 Da), TPB, AgTFA: (PS 92) ........................... 2 4 1.3.2 Poly(methyl methacrylate) ................................ ............................. 2 7 1.3.2. 1 PMMA (10,600 Da), DHB, NaTFA: (PMMA 10.6) ............. 2 7 1.3.3 Poly(ethylene glycol) ................................ ................................ ..... 2 9 1.3.3.1 PE G (5000 Da), Dithranol, NaTFA : (PEG 5) ................... 2 9 1.3.2 Deposition Morphology ................................ ................................ .. 3 2 1.3.2.1 Amorphous Polymer Sample Morphology ....................... 3 2 1.3.2.2 Semi Crystalline Polymer Sample Morphology ................ 3 3 1.3.2.3 Depositional Spatial Concentration ................................ 3 3 1.3.3 Cross Polarization Images ................................ ............................. 3 7 1.3.3.1 PS (2300 Da), RA, AgTFA: (PS 2 RA) ............................ 3 7 1.3.3.2 PS (2300 Da), TPB, AgTFA: (PS 2) ................................ 3 7 1.3.3.3 PS (92,600 Da), RA, AgTFA: (PS 92 RA) ....................... 3 8 1.3.3.4 PS (92,600 Da), TPB, AgTFA: (PS 92) ........................... 3 8 1.3.3.5 PMMA (10,600 Da), DHB, NaTFA: (PMMA 10.6) ............. 3 8

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ii 1.3.3.6 PEG (5000 Da), Dithranol, NaTFA: (PEG 5) ................... 3 9 1.4 Conclusion ................................ ................................ ................................ ... 4 7 1.5 Acknowledg ments ................................ ................................ ........................ 4 8 1.6 References ................................ ................................ ................................ .. 4 9 CHAPTER 2 : THE MEASUREMENT OF CHARGE FOR INDUCTION BASED FLUIDIC MALDI DISPENSE EVENT AND NANOLITER VOLUME VERIFICATION I N REAL TIME ................................ ................................ ............... 5 2 2.1 Intro duction ................................ ................................ ................................ .. 5 2 2.2 Experimental ................................ ................................ ................................ 5 6 2.2.1 Reagents and Materials ................................ ................................ 5 6 2.2.2 Charge Measurement Apparatus and Procedure ........................... 5 6 2.2.3 Charge Measurement Solutions and Procedure ............................ 5 9 2.2.4 Electrets Apparatus and Procedure ................................ ............... 5 9 2.3 Results and Data Analysis ................................ ................................ ........... 60 2.3.1 Charge Measurements ................................ ................................ .. 60 2.3.2 HEMA Electrets ................................ ................................ ............. 7 1 2.4 Conclusion ................................ ................................ ................................ ... 7 4 2.5 References ................................ ................................ ................................ .. 7 5 CHAPTER 3 : DIELECTRIC ANALYSIS OF POLY(METHYL METHACRYLATE) ZINC(II) MONO PINACOLBORANE DIPHENYLPORPHYRIN COMPOSITES ........ 7 7 3.1 Introduction ................................ ................................ ................................ .. 7 7 3.2 Experimental ................................ ................................ ................................ 8 2 3.2.1 Experimental Reagents ................................ ................................ 8 2 3.2.2 Zinc monoborate diphenyl porphyrin (Zn(II)Bpin DPP) Synthesis ................................ ................................ .......................... 8 2 3.2.3 Poly(methyl methacrylate) synthesis ................................ .............. 8 3 3.2.4 PMMA Zn(II)Bpin DPP composite synthesis ................................ .. 8 4 3.2.5 Instrumentation ................................ ................................ .............. 8 5 3.2.5.1 H 1 NMR ................................ ................................ ............ 8 5 3.2.5.2 UV/VIS Spectroscopy ................................ ...................... 8 5 3.2.5.3 Fluoresce nce Spectrometer ................................ ............ 8 5 3.2.5.4 Sample molding ................................ .............................. 8 6 3.2.5.5 Differential Scanning Calorimetry DSC ............................ 8 6 3.2.5.6 Dielectric analysis DEA ................................ ................... 8 7 3.2.6 Data Fitting ................................ ................................ .................... 8 7 3.3 Results ................................ ................................ ................................ ......... 8 7 3.3 .1 Dipole Moment Zn(II)Bpin DPP ................................ ..................... 8 7 3.3.2 UV vis Spectroscopy ................................ ................................ ..... 8 9 3.3.3 Fluorescence Spectroscopy ................................ ........................... 90 3.3.4 DSC ................................ ................................ ............................... 9 3 3.3.5 Dielectric analysis (DEA) ................................ ............................... 9 4 3.3.5.1 Permittivity ................................ ................................ ...... 9 5 3.3.5.2 Electric Modulus ................................ .............................. 9 9 ................................ .................... 10 ................................ ................................ ... 105 max ) ................................ .. 110 max ) ................................ 111 ................................ ........................... 112 3.3.5.6 Viscoelastic to Conductivity Relaxation ......................... 116

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iii 3.3.5.7 Conductivity Relaxation ................................ ................. 1 20 3.3.5.7.1 Proof 1 Argand Plots ................................ ....... 121 ............ 1 23 3.3.5.7.3 Proof 3 AC conductivity ................................ .. 1 27 3.3.5.7.3.1 DC Conductivity ............................... 1 30 DC max ) ................................ 1 32 3.3.6 Havriliak Negami Function ................................ ........................... 1 36 3.3.7 Tangent of Dielectric Loss Angle ................................ ................. 146 3.3. 8 PMMA Degradation ................................ ................................ ..... 1 51 3. 3. 8 .1 Unzipping of PMMA (Thermal degradation) ................... 1 51 3.3. 8 .2 PMMA Degradation Electric Modulus ............................ 1 56 3.3.8.3 PMMA Degradation AC Conductivity ............................. 1 61 3.4 Conclusion ................................ ................................ ................................ 1 64 3.5 Acknowledg ments ................................ ................................ ...................... 1 66 3.6 Reference s ................................ ................................ ................................ 1 66 CHAPTER 4: FUTURE WORK ................................ ................................ .................... 17 1 4.1 Contributions of Dissertation ................................ ................................ ...... 17 1 4.2 MALDI TOF with Induction Based Fluidics ................................ ................. 1 7 1 4.3 Electrets and monodisperse spheres ................................ ......................... 1 7 2 4.4 PMMA Zn(II)Bpin DPP ................................ ................................ ............... 1 7 5 4.4.1 Potential synthetic routes ................................ ............................. 1 7 6 4.5 References ................................ ................................ ................................ 1 79 ABOUT THE AUTHOR ................................ ................................ ................... END P AGE

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iv LIST OF TABLES Table 1. 1. Polystyrene retinoic acid AgTFA (PS 2 RA) characterization data ............... 1 6 Table 1 2. Change in Signal/Noise & Intensity (%) in volumetric equivalent depositions using IBF method compared to manual pipette/syringe pump for various polymer standards ................................ ............................ 1 6 Tab le 1. 3 Polystyrene,TPB, AgTFA (PS 2) characterization d ata ................................ 1 9 Table 1. 4. Polystyre ne (6550 Da), TPB, AgTFA (PS 6) characterization d ata ............... 2 2 Table 1. 5 Polystyrene(92,600 Da), TPB, AgTFA (PS 92) characterization d ata ........... 2 5 Table 1 6. Poly(methyl methacrylate) 10,600 (Da), DHB, NaTFA. (PMMA 10.6) characterization d ata ................................ ................................ ................... 2 8 Table 1. 7 Poly(ethylene glycol) (50 00 Da), Dithranol,NaTFA (PEG 5) characterization d ata ................................ ................................ .................... 30 Table 1.8(a). PS RA 2 volume 2 ) of I BF and MP de positions. ................................ ................................ ............................. 3 4 Table 1. 8 ( b ) PS 2 volume 2 ) of IBF and MP depositions ................................ ................................ .............................. 3 4 Table 1. 8 ( c ). PS 92 volume 2 ) of IBF and MP depositions. ................................ ................................ ............................. 3 4 Table 1. 8 ( d ). PMMA 10.6 volume 2 ) of IBF and MP depositions ................................ ................................ ........................ 3 5 Table 1. 8 ( e ). PEG 5 volume 2 ) of IBF and MP depositions. ................................ ................................ ............................. 3 5 2 ) reduction in percent of the IBF depositions when compared to micropipette depositi ons of equal volume and analyte ............. 3 6 Table 2.1(a). 0.33M HCl IBF charge depositional data for 11 to 400 nL. ...................... 6 3 Table 2.1(b). 0.166M HCl IBF charge depositional data for 11 to 400 nL. .................... 6 3 Table 2.1(c). 0.091M HCl IBF charge depositional data for 11 to 400 nL. .................... 6 4

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v Table 2.2(a). 0.33M Na Cl IBF charge depositional data for 11 to 400 nL. ..................... 6 7 Table 2.2(b). 0.166M Na Cl IBF charge depositional data for 11 to 400 nL. ................... 6 7 Table 2.2(c). 0.091M Na Cl IBF charge depositional data for 11 to 400 nL. ................... 6 8 Table 2.3. 2 HEMA with 2.0wt% Benacure TM 1153 IBF charge depositional data for 11 to 400 nL ................................ ................................ .................... 70 Table 3. 1. Dipole moment of Zn(II)Bpin DPP compared with common solvents ........... 8 9 Table 3.2 Summary of fluorescence decay lifetimes for composite samples (0.3 and 1.3wt%), metaloporphyrin Z n(II)BpinDPP, and the free base porphyrin H 2 BpinDPP ................................ ................................ ................... 9 2 Table 3.3 DSC glass transition (Tg) temperatures ( C) for PMMA and PMMA Zn(II)Bpin DPP composites at respective wt%s. ................................ ........... 9 3 Table 3 .4 Comparison of max max ) peak maximums at 300 Hz for PMMA and PMMA Zn(II)Bpin DPP composites. ................................ .... 110 Table 3.5 Comparison of apparent E a PMMA and PMMA Zn(II)Bpin DPP composites. ................................ ......... 111 Table 3.6 max orphyrin content trended lower max ) temperatures. ................................ ............. 113 Table 3.7 Vogel Fulcher fitting parameters for PMMA and PMMA Zn(II)Bpin DPP composites ................................ ............................ 116 Table 3.8 Dielectric relaxation strengths ( M) of samples tested ............................... 123 Table 3.9 Ionic conductivity apparent E a for PMMA and PMMA Zn(II)Bpin DPP composites ................................ ........................... 132 Table 3 .10 DC ) and electric loss apparent E a ................................ ................................ ....... 136 Table 3.11. H N fit parameters for PMMA and PMMA Zn(II)Bpin DPP c omposites 160 C ................................ ................................ .................. 139 Table 3 12(a). H N pa rameters 160 to 190 C for PMMA ................................ ........... 144 Table 3 12(b). H N parameters 160 to 190 C for PMMA Zn(II)BpinDPP 0.05wt% ..... 145 Table 3 12(c). H N parameters 160 to 190 C for PMMA Zn(II)BpinDPP 0.11wt% .... 145 Table 3 12(d). H N parameters 160 to 190 C for PMMA Zn(II)BpinDPP 0.9wt% ....... 145

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vi Table 3.13 PMMA Zn(II)Bpin DPP composites ................................ ........................... 149

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vii LIST OF FIGURES Figure 1.1. Typical molecular weight distribution for a narrow weight polymer s tandard ................................ ................................ ................................ ........ 1 Figure 1.2. Typical MALDI TOF spectra of a narrow molecular weight distributed polymer standard ................................ ................................ .......................... 3 Figure 1.3. Nanoliter Induction Based Fluidics (IBF) apparatus ................................ ...... 5 Figure 1.4 Components that make up varied MALDI TOF recipes used in this experiment ................................ ................................ ................................ ... 7 Figure 1.5. Cross polarization microscopy of a birefringent sample schematic ............... 9 Figure 1.6. (PS 2 RA) direct comparison of resolved M/Z peaks for Induction Based Fluidics (IBF) and micropipette (MP) at selected volumes (nL) ........ 17 Figure 1.7. MALDI Spectr a (Raw Signal) PS 2 RA Induction Based Fluidics (IBF) 250nL deposition ................................ ................................ ............... 17 Figure 1.8. PS 2 direct comparison of resolved M/Z peaks for Induction Based Fluidics (IBF) and micropipette (MP) at selected volumes (nL) ................... 20 Figure 1.9. MALDI Spectra (Raw Signal) PS 2 Induction Based Fluidics (IBF) 100nL deposition ................................ ................................ ........................ 20 Figure 1.10. PS 6 direct comparison of resolved M/Z peaks for Induction Based Fluidics (IBF) and micropipette (MP) at selected volumes (nL) ....... 23 Figure 1.11. MALDI Spectra (Raw Signal) PS 6 Induction Based Fluidics (IBF) 250nL deposition ................................ ................................ ....................... 23 Figure 1.12 Polystyrene 92,600 (Da) (PS 92) direct comparison of signal intensity for resolved M/Z peaks for Induction Based Fluidics (IBF) a nd micropipette (MP) at 1 00nL ................................ ................................ 26 Figure 1.13. Polystyrene 92,600 (Da) (Raw Signal) PS 92 Induction Based Fluidics (IBF) 100nL deposition ................................ ................................ 26 Figure 1.14. PEG 5 direct comparison of signal intensity for resolved M/Z peaks for Induction Based Fluidics (IBF), micropipette (MP) & Syringe pump (SP) at selected volumes (nL) ................................ ......................... 31

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vi ii Figure 1.15. MALDI Spectra (Raw Signal) PEG 5 Induction Based Fluidics (IBF) 500nL deposition ................................ ................................ .............. 31 Figure 1.16. Polystyrene (2300 Da.), retinoic acid, AgTFA cross polarization images in transmission (top) a nd reflected (bottom) for IBF and micropipette 100 to 500 nL depositions. ................................ ....... 41 Figure 1.17. Polystyrene (2300 Da.), tetraphenyl butadiene, AgTFA cross polarization images in transmission (top) and reflected (bottom) for IBFand micropipette 100 to 500 nL depositions. ................................ ........ 42 Figure 1.18. Polystyrene (92,600 Da.), retinoic acid, AgTFA cross polarization images in transmission (top) and reflected (bottom) for IBF and micropi pette 100 to 500 nL depositions ................................ ..................... 43 Figure 1.19. Polystyrene (92,600 Da.), tetraphenyl butadiene, AgTFA ) cross polarization images in transmission (left ) and reflected (right) for IBF and micropipette nL depositions ................................ ................................ 44 Figure 1.20. Poly(methyl methacrylate) (10,600 Da.), dihydroxy benzoic acid, NaTFA cross polarization images in t ransmission (top) and reflected (bottom) for IBF and micropi pette 100 to 500 nL depositions ..................... 45 Figure 1.21. Poly(ethylene glycol) (5,000 Da.), dithranol, NaTFA cross polarization images in transmission (top) and reflected (bottom) for IBF and micropipette 100 to 500 nL depositions. ................................ ....... 46 Figure 2.1. Reagents ................................ ................................ ................................ .... 5 6 Figure 2.2. Induction Based Fluidics (IBF) charge measurement apparatus to shield electromagnetic frequency radiation (EMF) interference from sens itive faraday cup measurements ................................ .................. 5 8 Figure 2.3. Electret manufacture apparatus using IBF and UV initiated polymerization of 2 HEMA with 2.0 wt% Benacure atop frozen CO 2 .......... 60 Figure 2.4. Varied molar concentrations of HCl charge (nC) versus surface area (nm 2 ) ................................ ................................ ................................ ... 6 2 Figure 2.5. Varied molar concentrations of NaCl charge (nC) versus surface area (nm 2 ). ................................ ................................ ................................ .. 6 6 Figure 2.6. 2 HEMA with 2.0wt% Benacure TM 1153 charge (nC) versus surface area (nm 2 ) ................................ ................................ ................................ ... 6 9 Figure 2.7. Poly( 2 HEMA) IBF dispensed droplets ................................ ........................ 7 2 Figure 2.8. 180nL p oly(2 H EMA) with 2.0wt% Benacure TM exhibiting electrostatic a ttraction toward metal spatula. ................................ .............. 7 3 Figure 3.1. Synthesis of Zn(II)Bpin DPP followed by zinc metallization ....................... 8 3

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ix Figure 3.2. Synthes is of poly(methyl methacrylate) ................................ ....................... 8 4 Figure 3.3. PMMA and PMMA Z n(II )Bpin DPP composite samples .............................. 8 4 Figure 3.4. Zn(II)Bpin DPP 8 9 Figure 3.5. UV vis spectrum of 1.964x10 6 M solution Zn(II)Bpin DPP in CH 2 Cl 2 .......... 90 Figure 3.6: Normalized absorption spectra in the visible region for the polymer samples as well as free Zn(II)Bpin DPP in ethanol ................................ ..... 9 1 Figure 3.7: Normalized emission spectra for all of the polymer samples as well as Zn(II)Bpin exc = 414 nm) ................................ ............. 9 1 Figure 3.8. DSC y axis stacked spectra of PMMA & PMMA Zn(II)BpinDPP (0 .05, 0 .11, 0.9 wt%) composites ................................ ................................ 9 3 Figure 3.9. Permittivity versus temperature ( C) ................................ ........................... 9 7 ................................ ....................... 9 9 max divergence ................................ ................................ .............................. 10 2 Figure 3.12. max relaxations ................................ ................................ ............................... 104 C) plots 0.3 Hz to 100 kHz ........... 107 C) plots 0.3 Hz to 100 kHz ................................ ................................ .................... 109 Figure 3 .1 5. Vogel relaxation times versus temperature (K) egion. ................................ ................................ .......... 115 ................................ ................................ 120 155 and 200 C ................................ ................................ ....................... 123 Figure 3.18. Starkweater plots PMMA and PMMA Zn(II)Bpin DPP composites .......... 1 26 AC ) (S/m) versus frequency (Hz): between 130 to 270 C ................................ ................................ .......................... 129 DC conductivity (S/m) versus temperature (C) for PMMA, PMMA ZnBpin DPP 0.05 wt%, PMMA ZnBpin DPP (0.11 wt%), and PMMA ZnBpin DPP (0.9 wt%) ................................ .......................... 1 31

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x DC versus inverse temperature (K) plots of PMMA Control and PMMA Zn(II)Bpin DPP composites (0.0 5 wt%, 0.11 wt%, and 0.9 wt%) ................................ ................................ ........................... 1 32 Figure 3.22. DC max ) versus 1000/T (K) demonstrating good temperature and E a agreement proving conductivity relaxation ...... 1 35 M o (low frequency) and M axis)) intercepts ........................ 138 Figure 3.24. Havriliak Negami relaxation plots 160 and 190 C. ................................ ............................. 143 Figure 3.25. max ) order PMMA < 0.11 wt% < 0.05 wt% < 0.09 wt% ................................ .............. 144 Figure 3.26. Current voltage diagra m of a dielectric showing loss .............................. 147 C) for PMMA and P MMA Zn(II)Bpin DPP composites ................................ ......................... 1 50 C ) ................................ .......................... 1 55 Figure 3.29. Poly(methyl methacrylate) thermal degradation via end group scission schematic. ................................ ................................ ....... 156 Figure 3.30. Average relaxation time, ,versus temperature ( C) from the conductivity region (160 to190 C) and beyond to first part of PMMA degradation (190 to 270 C) ................................ ......................... 159 .......... 160 Figure AC (S/ m) versus log frequency (Hz). ................................ ...................... 163 Figure 4.1. Cross linking molecules for poly(2 HEMA) electrets ................................ .. 17 3 Figure 4.2 Cinnamic acid p hotodimerization in solid state ................................ .......... 175 Figure 4.3. Monomers that can prod uce hydrophilic porous polymers ........................ 17 6 Figure 4.4. Heck Reaction coupling porphyrin to 2 HEMA via oxidative addition then elimination. ................................ ................................ .................... 17 8 Figure 4.5. Fp (CpFe(CO) 2 ) ................................ ................................ ....................... 17 8 Figure 4.6. Pd catalyzed C O insertion using Fp to protect the olefin. ......................... 1 79

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xi LIST OF EQUATIONS Eq. 1.1. M olecular number average molecular weight (M N ) ................................ ............. 2 Eq. 1.2. M olecular weight average molecular weight (M W ) ................................ .............. 2 Eq. 1.3 P olydispersity (PD) ................................ ................................ ............................ 3 Eq. 1.4. P olymer spread (P SP ) ................................ ................................ ........................ 3 Eq. 1.5 Resolution (R s ) ................................ ................................ ................................ 1 2 Eq. 2.1 Hagen Poiseuille equation ................................ ................................ ............... 5 4 Eq. 2.2 Force on charged droplet in an electric filed ................................ .................... 5 5 Eq. 2.3 s Law ................................ ................................ ................................ ... 5 5 Eq. 2.4 Volume of a sphere ................................ ................................ ........................ 5 6 Eq. 2.5 Surface area of a sphere ................................ ................................ ................. 5 6 Eq. 2.6 Surfac e area to volume relationship ................................ ................................ 5 6 Eq. 3.1 Complex Permittivity defined ................................ ................................ ........... 9 4 Eq. 3.2 Permittivity (d ielectric constant) defined ................................ .......................... 9 4 Eq. 3.3 Loss Factor (dielectric loss) defined ................................ ................................ 9 4 Eq. 3.4 Debye equation (complex permittivity) ................................ ............................. 9 5 Eq. 3.5 Permittivity (dielectric constant ) ................................ ................................ .... 9 5 Eq. 3.6 Loss Factor (dielectric loss ) ................................ ................................ ......... 9 5 Eq. 3.7 Ionic conductivity ................................ ................................ ............................. 9 5 Eq. 3.8 Complex electric modulus (M*) ................................ ................................ ........ 9 9 Eq. 3.9 Arrhenius equation: (ln frequency versus the reciprocal temperature) ........... 105 Eq. 3.10 Vogel Fulcher equation ................................ ................................ ............... 113 Eq. 3.11 Debye semicircle equation ................................ ................................ .......... 121

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xii Eq. 3.12 Dielectric Streng th ................................ ................................ ...................... 122 Eq. 3.13 Starkweather: complex permittivity independent of viscoelasticity ............... 1 24 Eq. 3.14 Starkweather: electric modulus independent of viscoelasticity ..................... 1 24 Eq. 3.15 Starkweather: electric loss modulus independent of viscoelasticity .............. 1 24 Eq. 3.16 Starkweather: characteristic relaxation time ................................ ............... 1 24 Eq. 3.17 Starkweather: electric modulus ................................ ................................ .... 1 24 Eq. 3.18 AC Conductivity ................................ ................................ ........................... 1 2 7 Eq. 3.19 Conductivity power law relationship ................................ ............................. 1 2 7 Eq. 3.20 DC versus the reciprocal temperature) ................... 1 3 1 Eq. 3.21 Havriliak Negami modified complex permittivity equation ............................ 1 36 Eq. 3.22 Havriliak Neg ami modified electric modulus ................................ ................ 1 38 Eq. 3.23 Havriliak Negami modified electric loss modulus ................................ ......... 1 38 Eq. 3.24 ................................ ................................ ................................ ... 1 39 Eq. 3.25 ned ................................ ................................ ............ 1 39 Eq. 3.26 Charging current (90 out of phase) defined ................................ ................ 1 46 Eq. 3.27 Loss current (in phase) defined ................................ ................................ ... 1 46 Eq. 3.28 ................................ ................................ .......................... 1 47

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xiii LIST OF SYMBOLS AND ABBREVIATIONS relaxation strength C: degree Celsius. C: coulomb, SI unit electric charge 6.24151 10 18 protons or 6.24151 10 18 electrons C o : r eference capacitance. D: measure of fragility related to depths and density in the minima in the potential energy landscape of the glass former. Da : Dalton, unit of mass, equal to 1 u. Debye: (10 18 10 30 Cm ). E: External Applied electric field E a : Apparent activation energy f : frequency. F: force. f o : f requency at infinite temperature (pre exponential factor) FWHM: 1/2 full width at half maximum. Hz: Hertz (cycles/s). i: ( 1) 1/2 J: 2 ). K: Kelvin. kcal: kilocalorie, energy needed to increase the temperature of 1 kilogram of water by 1 C kHz: kiloHertz (10 3 Hz). l: length.

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xiv L : l iter ln natural log M : complex electric modulus MM: molar mass m: meter : electric storage modulus : electric loss modulus M : electric m mg: milligram (10 3 gram) M N : number average molecular weight mol : mole ( 6.02214210 23 u). M p : m ost probable peak, statistically in greatest amount. M S : e lect ric modulus at zero frequency M W : weight average molecular weight M X : molecular weight of a molecule corresponding to a degree of polymerization x n : nano (10 9 ) nC: nanoc oulomb nm: nanometer N X : the total number of molecules of length x P : p ressure Pa: pascal (Newton/meter 2 ). PD: polydispersity psi: pounds per square inch. P SP : width of the spectrum without bias being caused by the magnitude of the molecular weight of the polymer q: charge.

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xv r : radius. R: resistance (Ohm) or i deal gas law constant R 2 : s tatistical measure of how well a regression line approximates re al data points. RMS: root mean s quare R s : r esolution S/N: signal to n oise ratio. S: s iemen s = (1/r esistance). SA: surface a rea. STP: Standard Temperature and Pressure t : time T: t emperature t angent of the loss angle. Tg: g lass transition temperature T o : t emperature where extrapolated relaxation time diverges. V: v olume W/g: w atts per gram (W = J/s) wt%: weight percent (mass/mass) delta, chemical shift or angle of dissipation : delta, d ifference complex permittivity. p ermittivity (dielectric constant) loss f actor (dielectric loss) 0 : absolute permittivity of free space (8.854 X 10 14 F/cm) or r : u nrelaxed at high frequency. S : static dielectric permittivity at zero frequency.

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xvi viscosity. l ambda, wavelength. mu, micro (10 6 ) or mean (average) sta ndard deviation or ionic conductivity. 0 : Pre exponential factor (conductivity at infinite temperature). 2 : variance. AC : a lternating current conductivity (S/m) DC : d irect current conductivity (S/m) : 1 ) average relaxation time o : extrapolated relaxation time at infinite temperature. : 1 ) : characteristic time u: atomic mass unit.

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xvii ABSTRACT Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI TOF) mass spectroscopy is used in the characterization of synthetic polymers. MALDI allows for determination of: modal, most probable peak (M P ), molecular number average (M N ), molecular weight average (M W ), poly dispersity (PD), and polymer spread (P SP ). We evaluate a new sample preparation method using Induction Based Fluidics (IBF) to kinetically launch and direct nanoliter volumes to a target without contact. IBF offers signal improvement via field enhanced c rystallization. This is the first study to discuss filed enhanced crystallization in MALDI sample preparation. IBF can increase signal/noise (S/N) and signal intensity for polystyrene (PS), poly(methyl methacrylate) (PMMA), and poly(ethylene glycol) (P EG ) across a mass range of 2 500 to 92,000 Da showing more accurate P SP Increases in S/N range up to: 279% for PS, 140% for PMMA, and 660% for PEG. Signal intensities increased up to: 438% for PS, 115% for PMMA, and 166% for PEG. Cross polarization microsc opy indicates dramatic morphology differences between IBF and micropipette. Finally, we speculate as to why IBF nanoliter depositions afford higher S/N values in experiments conducted in different instrumental configurations even without optimization. Ne xt we sought to investigate whether nanoliter volumes of concentrated polar liquids and organic monomers launched to targets using IBF can be verified through the real time charge measurements. We show that using a nanoliter IBF dispensing device and nano coulomb meter, charge measurements made on nanoliter drops in real time are

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xviii ne arly instantaneously, in real time. Implications are presented from these IBF measurement observations on improving/monitoring MALDI quantitation and its quality control. Polymer dye interactions were further investigated using PMMA composites made from a polar metalloporphyrin [5 (4',4',5',5' tetramethyl[1',3',2']dioxaborolan 2' yl) 10,20 diphenylporphyrinato]zinc(II) (Zn(II)Bpin DPP) in select weight %s (wt% s ). Fluorescence s pectroscopy has revealed that the porphyrin was well dispersed within the comp osite. Differential Scanning Calorimetry (DSC) showed that porphyrin acted as an antiplasticizer raising the glass transition (Tg) from 105 C to 123 C. Dielectric Analysis (DEA) was performed in the frequency range of 0.3 Hz to 100 kHz between 150 to 2 70 C. 190 C. This study brings analysis to 270 C which is start point for the first part of PMMA degradation. Thus forwarding DEA can be used to evaluate PMMA degradation. apparent activation energies (E a ) for the molecular relaxations are present AC ) DC evaluated between 1 Hz to 100 kHz was shown to increase with porphyrin loading although locally affected by free vo lume restriction. Hav riliak Negami (H N) equ ation was fit using the complex electric modulus (M ) modified form and was performed on the conductivity region 160 to 190 C and degradation region 190 to 270 C Relaxations above the Tg were proven to be conductivity relaxations using four proofs Th is is the first study to investigate PMMA degradation DEA with the complex electric modulus, M*,

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xix revealing a unique occurrence of increasing central relaxation times (s 1 ) and reducing temperature of 220 C was reached supporting current literature of the first of a two part degradation process that proceeds via end chain scission.

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1 CHAPTER 1 : ELECTRIC FIELD ENHANCED S AMPLE PREPARATION FOR SYNTHETIC POLYMER MALDI TOF MASS SPECTROMETRY VIA INDUCTION BASED FLUIDICS (IBF) 1. 1 Introduction Matrix assisted laser desorption/ionization time of flight (MALDI TOF) mass spectroscopy is currently widely used in the structural character ization of synthetic polymers. Synthetic polymers are not monodisperse and are comprise d of a distribution of molecular weights [1] Due to this distribution of molecular weights more than one average molecular weight is needed to sufficiently characterize a polymer sample [1] Figure 1. 1 illustrates a typical narrow molecular weight polymer standard sample spectra from gel permeation chromatography (GPC) highlighted with the different ways to characterize the molecular weight distribution. Figure 1. 1. Typical mol ecular weight distribution for a narrow weight polymer standard.

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2 Polymer characterization by MALDI allows for the rapid determinatio n of: modal, most probable peak (M P ), molecular number average (M N ) E q. 1 1 molecular weight average (M W ) E q. 1. 2, polydispersity (PD) E q. 1. 3 and polymer spread (P SP ) E q. 1. 4 [2 5] ( Eq. 1. 1) and ( Eq. 1. 2) Where M X is the molecular weight of a molecule corresponding to a degree of polymerization x, N X the total number of molecules of length x, M N the number average molecular weight, and M W is the weight average molecular weight. In MALDI TOF the signal obtained is different than that of Figure 1 1 in that the smooth Gaussian distribution is quantized in discrete spikes, Figure 1 2 In the case of polymer MALDI TOF the spectra reveal the discrete molar mass distributions allowing for the rapid determination of N X M X through the peak intensity, M X from the adjusted (ion subtracted) mass to charge (m/z) ratio, and the molar mass of the monomer repeat unit, Figure 1 2 ( a c ) respectively [6]

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3 Figure 1. 2 Typical MALDI TOF spectra of a narrow molecular weight distributed polymer standard. (a) the vertical line of peak intensity which represents N X M X (b) Mass to charge ratio (m/z) mass + ion (must be adjusted subtract ion) to yield M X .(c) Monomer Repeat Unit mass distance between neighboring peaks ( M X ) ( Eq. 1. 3) and ( Eq. 1. 4) PD is used to estimate the breadth of the distribution by the ratio of molecular weight averag e to molecular number average. P SP defined by Tatro et al is the width of the spectrum without bias being caused by the magnitude of the molecular weight of the po lymer [3]. To calculate P sp a Gaussian distribution is formed by aggregating the observed peaks about the M p Where | 1/2 | (Full width at half maximum (FWHM)) is the absolute value difference of the width at half height, and MM is the molar mas s of the monomer repeat unit. This allows for the determination of the number of monomer units within 1.1775 standard deviation from the M P which can make classification and comparison simpler since PD can be deceptive when comparing low molar mass t o high molar mass polymers. Preparation of the MALDI target is a crucial step in obtaining optimum spectra. In 2006, G. Montaudo et al. reviewed advances in sample preparation techniques that

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4 improved high mass resolution, end group identification, and se quence analysis [1]. These improvements have led to more accurate characterizations of polymers. Additional improvements in MALDI sample preparation techniques such as layering, solvent free sample preparation, surface preparations/coatings, and the addi tion of sugars have also proven to be excellent methods for MALDI sample preparation improvement for low molecular weight polymers/proteins yielding increased signal/noise (S/N) and resolution (Rs) [7 14] In 2008 Tu et al reported a novel sample preparation technique for io nic liquid matrices (ILE) and conventional solid matrices using an intact protein bradykinin (BK), a 9 amino acid peptide chain with a MM of 1060.21 Da, that employed the use of Induction Based Fluidics (IBF) to deposit nanoliter volumes [15] This patented system, Figure 1 3 is effectively a microliter syringe that uses electric induction in a process termed Induction Based Fluidics (IBF) to transport and optionally treat liquids [16]

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5 Figure 1 3 Nanoliter Induction Based Fluidics (IBF) apparatus:(A) Stepper motor controller;(B) Nanoliter Induction Power unit;(C) Stepper motor;(D) Nanoliter LLC Needle (i.d 50/ o.d. In IBF, a charge is induced on the liquid by passing the fluid through an electric field inductively, not conductively as in electrospray ionization (ESI) [16, 17] As such, in IBF there are no faradaic processes, only capacitance based ones, unlike ESI. Therefore, the inductive charging process is elegant in that it performs no unwanted electrochemistry, keeping the an alyte intact [17] The physics behind IBF shows that unlike piezoelectric, sound, or other technologies that are applied to transp ort liquids at low volumes, IBF kinetically la unches drops to targets and can dynamically direct the liquids to targets in flight [16, 17] Tu et al [15] had shown, with equal molar concentrations of analyte, even if the same volume is dispensed the sample planar area of IBF depositions is smaller. This result creates a more spatially concentrated sample ( more hot spots) using IBF which generated improved MALDI data. This study also reported that nanoliter quantities of ionic liquid matrices and solid matrices exhibit major improvement in both MALDI sensitivity ( ca. 10 x ) and reproducibility ( ca. 5x) using IBF for

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6 the analysis of proteins [15] Additionally, Tu et al. reported seeing a 40 % increase in signal enhancement from IBF over micropipette depositions utilizing conventional solid matrices and showed I BF improved the signal of BK. Over the last decade, our laboratory has studied the alignment of polymer molecules in electric fields, via dielectric spectroscopy (DEA) [18 24] and this prompted us to delve deeper into the reason for polymers. It is widely accepted that MALDI sample uniformity greatly enhances the quality of MALDI spectra. A review by Hoteling et al. correlated signal to noise ratio with the solubility of matrix and analyte [25] Shot to shot and spectrum to spectrum va riability analyte from the matrix making signals less homogenous which lowers signal quality and intensity. Hanton and Owens [26] report, in addition to the solubility in the liquid phase, the relative rate of precipitation of the matrix and analyte from the combined termed ility is also important for obtainin g high quality MALDI spectra. Solid phase solubility relates to the relative positions and orientations of analyte, ionization agent, and matrix as these precipitated alignments are also important to obtain good polymer MALDI signals [26] In addition to the smaller more uniform sample size deposits (pL to nL ) produced by the nanoliter IBF, the induced field used in sample preparation has an additional benefit with regards to sample segregation. Studies have shown that an induced electric field has the beneficial effect of increasing the solubility of binary, polymer solvent, and polymer polymer solutions [27 32] The induced electric field may reduce segregation and improve solid phase solubility resulting in beneficially enhanced spectra.

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7 In order to evaluate the benefit of Induction Based Fluidic (IBF) depositions, we applied this sample preparation technique to: (1) three common polymer standards Figure 1. 4 ( a ) (2) a mass rage of polymers ranging from ca. 2,500 to ca. 92,000 Da (3) different matrices and ion sources Figure 1. 4 ( b ) and ( c ) respectively Polymers generally exhibit varying degrees of crystallinity and amorphous behavior The morphology of the polymer standards used may be important to distinguish when evaluating IBF results; polystyrene and poly(methyl methacrylate) are amorphous while po ly(ethylene glycol) is semi crystallin e (at low molecular weights). Figure 1 4 ( a ) Figure 1 4 ( b ) Figure 1 4 ( c ) Figure 1. 4 Components that make up varied MALDI TOF recipes used in this experiment. (a) Structures of polymer standards utilized. (b) MALDI TOF recipe matrix molecules. (c) MALDI TOF ion source molecules.

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8 I high local deposition variability and this variability leads to les s reproducible signals [33, 34] A consequence of this heterogeneity of deposition is that characteristic data (M N & M W ) have high degrees of variance and are not accurate enough for polymer classification. The need for accurate polymer characterization has led to expensive, yet accurate and precise methods such as electrospray ionization (ESI), a conductive technique which sometimes can fragment analytes and gel permeation chromatography (GPC) which is a relative standard and not applicable to all synthetic polymers. IBF is evaluated here as an additional platform to deliver accurate and precise characteristic data when used in polymer sample preparation for MALDI TOF We also compared the morphologies of IBF and micropipette depositions, using cross polari zation microscopy. Cross polarization microscopy allows for the investigation of birefringent materials Figure 1 5 A birefringent material can split plane polarized light into two separate rays: the ordinary ray (unchanged by sample) and the extra ordinary ray (refractivi l y altered ray) [35] These two rays will have interference producing color images when the two polarization lenses are set to extinction [35] Differences in observed color can indicate crystal structure and analyte thickness differences Images obtained show discontinuous crystallization for micr opipette depositions that may be caused by dissimilar rates of evaporation, thickness of deposition, or altered crystal lattice morpholog y These dissimilar crystalline areas are still being investigated. It has long been accepted from previous research that smaller homogenous crystals are the key to producing enhanced MALDI signals [34, 36] We offer evidence to the contrary through the coupling of cross polarization images with MALDI spectra that result in larger more dense crys tal matrices produced via IBF.

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9 Figure 1. 5 Cross polarization microscopy of a birefringent sample schematic [35] With all of these observatio ns we speculate that nanoliter IBF depositions in addition to increasing spatial concentration, reducing chemical noise, and other complications such as ion clusters, that, in fact, the electric field in IBF itself may, in part, be responsible for enhancing the MALDI signal observed by us for synthetic polymers and others for proteins and peptides. 1. 2 Experimental 1.2.1 MALDI Reagents MALDI TOF MS analysis was performed on five synthetic polymer samples: (1) a 2300 Da polystyrene sample (Scientific Polymer Products Inc., Ontario, Canada), (2) a 5000 Da poly(ethylene glycol) sample (NIST supplied: Scientific Polymer Cat #500 Case 9004 74 4, Gaithersburg, MD), (3) a 6550 Da polystyrene sample (NIST SRM 1487, Gaithersburg MD), (4) a 10,600 Da poly(methyl methacrylate) sample (NIST, Gaithersburg MD), and (5) a 92,600 Da polystyrene sample (American Polymer Standards Corp., Mentor, Ohio USA). Matrixes used in these experiments were retinoic

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10 acid (RA) (Sigma Aldrich, St. Loi us MO), 1,1,4,4 tetraphenyl 1,3 butadiene (TPB) (Aldrich Chem Co., Milwaukee, WI), dithranol (Sigma Aldrich, St. Louis, MO), and 2,5 dihydroxybenzoic acid (DHB) (Sigma Aldrich, St. Louis, MO) that was purified by 1 deionize d H 2 O to remove excess sodium from manufacture source. Salts used in these experiments were sodium trifluoroacetate (NaTFA) and silver trifluoroacetate (AgTFA) (Sigma Aldrich, St. Louis MO). The solvent used was tetrahydrofuran (THF) HPLC grade (Fischer C hemica ls Fair Lawn, New Jersey USA). 1. 2.2 Sample Recipes and Preparation The six synthetic polymer samples were prepared using THF as the solvent in the following manner: (1) (PS 2 RA) 5mg/mL polystyrene (M n 2300, M w 2514), 40mg/mL RA ,5mg/mL AgTFA. (2) (PS 2) 5mg/mL polystyrene (M n 2300, M w 2514), 45mg/mL TPB ,5mg/mL AgTFA. (3) (PEG 5) 5mg/mL poly(ethylene glycol) 5000 Da, 40mg/mL Dithranol, 5mg/mL NaTFA. (4) (PS 6) 5mg/mL polystyrene (M n 6550), 45mg/mL TPB, 5mg/mL AgTFA. (5) (PMMA 10.6) 5mg/mL poly( methyl methacrylate) (M n 10,600), 40mg/mL DHB, 5mg/mL NaTFA. (6) (PS 92) 7mg/mL polystyrene (M n 92,600 ) 45mg/mL TPB, 5mg/mL AgTFA. All recipes were mixed in [1:10:1] ratio respectively. Samples were deposited onto MALDI targets using an Eppendorf 0.1 2. micropipettor (MP) in sizes ranging 100 500nL, nanoliter induction based fluidics (IBF) device in sizes ranging 100 500nL, and KDS 100 single syringe basic infusion pump (SP) (Holliston, MA) size of 100nL.

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11 1. 2.3 MALDI TOF MS Calibration To minimize b ias, MALDI TOF equipment used in this experiment were carefully optimized following guidelines and suggestions reported by Guttman [37] and Wetzal et al. [38] o f the polymers division at NIST. Mass calibration, instrument optimization for S/N, matrix and polymer concentration, detector voltage, and time delay were optimized as recommended to ensure high quality and high resolution MALDI spectra [37, 38] Polymer mass spectra were obtained for experiments using samples PS 2, PEG 5, PS 6, and PS 92 using a Voyager rkstation (Applied Biosystems, Foster City, CA). Insulin and Cytochrome C were used as the standards for external calibration. This instrument was equipped with a nitrogen laser (337 nm), and data were obtained by using the linear acquisition mode under de layed extraction conditions. Accelerating voltage was +25kV and laser shots setting from 750 1000. The laser shot values differed due to the physical amount of sample a vailable on the MALDI target. Samples were further individually optimized for signal to noise having the following values for grid and delayed extraction: PS 2 (90.0%, 300ns); PEG 5 (94.5%, 400ns); PS 6 (95.0%, 350ns) and PS 92 (96.5%, 700ns). Polymer mass spectra for PMMA 10.6 were obtained using a Bruker (Billerica, MA) Reflex II MALDI TOF calibration mix consisting of a multipoint calibration with a quadratic fit using Angiotensin II, Angiotensin I, Substance P, Bombesin, ACTH(1 17) and ACTH(18 39). T he acceleration voltage was +25 kV and ions were measured in the linear mode. Delayed extraction was optimized for signal to noise for the necessary mass range and the delay (450ns) was employed for the collection of all data. A nitrogen laser at 337 nm a nd a 3 ns pulse width was utilized.

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12 1. 2.4 MALDI Sampling Method & Data Analysis MALDI spectra consisted of the summation of the total number of ions obtaine d from 750 1000 laser shots. The laser remained in motion to prevent biases in the molecular mass d istribution due heterogeneity regardless of the method of sample application to the MALDI probe. The final MALDI spectrum was an accumulation of the sum of the total laser shots. Resolution (R s ) was calculated by dividing mass (m) by the change in mass a 1/2h ) E q. 1. 5 accounting for the RMS of the baseline. (Eq. 1. 5) M n M w PD, Psp, S/N at M p and Resolution at M p were obtained for all sample runs with the Voyager DE STR. S/N at M p was obtained for samples run on the Bruker Reflex II. Results were confirmed from additional sample sets tested having a sample set size (n) for each depositional method and respective volume of n = 4 or greater. 1. 2.5 Nanoliter Induct ion Based Fluidic (IBF) Device Figure 1 3 shows the nanoliter dispensing device, (Nanoliter,LLC,Henderson, Nevada, USA). The device co nsists of a digital controller F igure 1 3 ( a ) a programmable power unit and related electronics and an optional foot pedal F igure 1 3 ( b ) housing with stepper motor, F igure 1 3 ( c ) and inductor F igure 1 3 ( d ) The device employed a 10 Hamilton syringe, F igure 1 3 ( e ) which was equipped with a fused silica capillary needle, although other types of syringes can be employed in the device, suc h as a laser machined inductors.

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13 1. 2 .6 Cro ss Polarization Microscopy A LECA DMRX cross polarization microscope outfitted with a LEICA DCF 290 imaging camera was used to acquire cross polarization images of the samples deposited via micropipette and nanoliter IBF device. Via this technique, two polarized planes of light set in extinction allow for the analysis of crystal morphology through the observation of the bi re fringence of the sample. Similar crystals with similar orientation will appear homogenous when in comparison to one another though their director may have diffe rent values. This is a simple tool to find discontinuities and evaluate homogeneity of crystal formations where traditional optical microscopy may not produce an image. Images were processed using Leica A pplication Suite 3.1 software. 1. 3 Results and Dis cussion From the work of Tu et al. [15] an apparent counter intuitive observation that less volume (nL volumes as compared to L volumes) yields higher signal to noise values for proteins, peptides and synthetic polymers has been observed. These experiments conducted on different instruments in positive ion linear mode a nd positive ion reflectron mode suggest that there may be a number of factors contri buting to these observations. Tu et al. and this study have shown that I BF has the ability to spatially concentrate depositions, the depositio n occupies less planar area. Incoming photons will then have analytical ion of interest from use of the IBF method, in direct volume comparison. So the ability of IBF to concentrate analyte in nL spots may increase the probability that any given photon can generate an analytical ions of interest. would be less areas on the target that would generate noise, i.e., those spots devoid of

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14 analyte that contains only matrix, that can only produce noise. Karas et al. [39] have ions. We forward here that, in fact, with nL depositions one not only increases the probability to create more analytical ion of interest but the analytical ion has a much lower probability to be neutralized, as there is simply much less ionized matrix per sh ot. Therefore, both an increase in ion creation from a spatial perspective and a decrease in ion destruction processes in MALDI steps may increases the signal and reduce the noise when IBF nanoliter depositions are employed in any MALDI configuration. Fur thermore, Debye and Kleboth, in 1962, have shown electric fields increase solubility by reducing the free energy of mixing when an electric field is applied to a binary solution that is in the vicinity of the critical point [27] This phenomenon was expanded to polymer solutions and further investigated by Wirtz et al. where they concluded that a stationary electric field lowered the coexist ence and spinodal curves of a polymer solvent system, making components more soluble when subjected to an external electric field [28, 29] Moreover an applied external electric field has been shown to alter the morphology of crystallization where precipitates formed under electric field were found to be ca 10 to 100 times larger sized [40, 41] 1. 3.1 Polystyrene 1. 3.1 1 PS (2300 Da), RA, AgTFA: (PS 2 RA) Table 1 1 summarizes characterization data for PS 2 RA obtained from MALDI. Included in this table are number (M n ) and weight (M w ) average, polydispersity (PD), polymer spread (P SP ), signal to noise (S/N), resolution (R s ) at modal (M p ), laser shots, and intensity [1, 4, 42] PS 2 RA data in T able 1. 2 lists the percent change in S/N and

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15 Intensity for volume to volume comparisons of IBF to MP. IBF generally showed an increase in S/N and R S A comparison of IBF to MP depositions volume of 250nL shows that IBF the improved S/N, an increase of 279%, and improved signal intensity, an increase of 34.3%. These improvements in signal led to a more accurate rendering of P SP In this case, the P SP ed the overall signal quality, F igure 1. 6 P SP shows four less monomer repeat units within FWHM of the M P Figure 1. 7 shows the raw MALDI spectra obtained for the optimum PS 2 RA IBF deposition volume of 250nL

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16 Table 1.1. Polystyrene retinoic acid AgTFA (PS 2 RA) characterization data. (@ M P ) Laser Shots (PS RA 2) M N M W PD P SP (S/N) (S/N) (RSD%) Intensity (RSD%) Rs IBF 500nL 2320 2561 1.1 19 67 8.85 (13.06 %) 1026 148.2 (14.4%) 342 1000 IBF 250nL 2360 2561 1.08 17 131 7.8 (5.94%) 3901 196.4 (5.03 %) 489 750 IBF 100nL 2358 2595 1.1 17 70 4.97 (6.9%) 694 43.6 (6.3%) 379 750 MP 250nL 2395 2609 1.08 21 34.5 2.61 (12.45%) 2904 154.7 (13.9%) 277 750 MP 500nL 2391 2616 1.09 22 21 3.87 (11.23%) 1116 136.2 (4.7 %) 319 1000 Table 1.2. Change in Signal/Noise & Intensity (%) in volumetric equivalent depositions using IBF method compared to manual pipette/syringe pump for various polymer standards. PS RA 2 PS 2 PS 6 PS 92 PMMA 10.6 PEG 5 S/N Intensity S/N Intensity S/N Intensity S/N Intensity S/N Intensity S/N Intensity IBF 500 219% 8.10% 31.9% 12.5% 15.4% 9.2% --140% 55% 660% 166.4% IBF 250 279% 34.30% 75% 438% 68.20% 303.5% --103% 115% 52.2% 18.1% IBF 100 ------190% 128% --142% 16.9%

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17 Figure 1. 6. (PS 2 RA) direct comparison of resolved M/Z peaks for Induction Based Fluidics (IBF) and micropipette (MP) at selected volumes (nL). Figure 1. 7 MALDI Spectra (Raw Signal) PS 2 RA Induction Based Fluidics (IBF) 250nL deposition

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18 1.3.1.2 PS (2300 Da), TPB, AgTFA (PS 2) Table 1. 3 summarizes all the data for PS 2 obtained from MALDI. Included in this table are M n M w PD, P SP S/N, R s at M p laser shots, and intensity. PS 2 data in T able 1. 2 lists the percent change in volume to volume c omparisons between IBF and MP. The IBF method had increased S/N, R S and intensity. Comparing IBF with MP at 250nL showed an improved S/N and intensity. Increase of 75% and 438% respectively. Furthermore, IBF 100nL depositions had shown even larger gains in S/N and R S for this polymer standard. IBF deposition improves the overall signal quality and is seen in F igure 1. 8 The better quality signal produced changes P SP value, adding three more monomer units within the FWHM of the M P Figure 1 9 shows the raw MALDI spectra obtained for the PS 2 IBF deposition volume of 100nL.

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19 Table 1.3. Polystyrene,TPB, AgTFA (PS 2) characterization data. (@ M P ) Laser Shots (PS 2) M N M W PD P SP (S/N) (S/N) (RSD%) Intensity (RSD%) Rs IBF 500nL 2361 2599 1.1 18 2723 102.8 (3.7%) 1.80E+04 1184 (6.5%) 358 1000 IBF 250nL 2258 2545 1.12 19 3186 131.3 (4.1%) 4.90E+04 2483 (5.06%) 358 750 IBF 100nL 2299 2564 1.11 19 3865 205.3 (5.3%) 4.80E+04 2776 (4.75%) 395 750 MP 500nL 2415 2640 1.09 16 2065 82.7 (4.0%) 1.60E+04 989.9 (6.2%) 276 1000 MP 250nL 2338 2594 1.1 16 1820 77.2 (4.2%) 9.10E+03 1388 (15.3%) 275 750

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20 Figure 1 8 PS 2 direct comparison of resolved M/Z peaks for Induction Based Fluidics (IBF) and micropipette (MP) at selected volumes (nL). Figure 1. 9 MALDI Spectra (Raw Signal) PS 2 Induction Based Fluidics (IBF) 100nL deposition

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21 1.3.1.3 PS (6000 Da), TPB, AgTFA: (PS 6) Table 1. 4 summarizes all the dat a for PS 6 obtained from MALDI. Included in this table are M n M w PD, P SP S/N, R s at M p laser shots and intensity. PS 6 data in T able 1. 2 lists the percent change in volume to volume comparisons of IBF and MP. IBF showed an increase in S/N and Intensity. Comparing IBF with MP at 250nL show ed improved S/N and intensity. Increase of 6 9.2% and 303.5% respectively. IBF deposition improved the overall signal quality and is seen in Fi gure 1. 10 The better quality signal produced changes P SP value, adding four more monomer units within FWHM of the M P Figure 1. 11 shows the raw MALDI spectra obtained for the optimum PS 6 IBF deposition volume of 250nL.

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22 Table 1.4. Polystyrene (6550 Da), TPB, AgTFA (PS 6) characterization data. (@ M P ) Laser Shots (PS 6) M N M W PD P SP (S/N) (S/N) (RSD%) Intensity (RSD%) Rs IBF 500nL 6525 6660 1.02 20 97.5 8.6 (8.8%) 1248 68.9 (5.5%) 790 1000 IBF 250nL 6587 6770 1.02 23 147.5 6.7 (4.6%) 6101 141.4 (2.3%) 551 750 IBF 150nL 6510 6654 1.02 22 111 7.4 (6.7%) 4280 94.5 (2.2%) 472 750 IBF 100nL 6501 6644 1.02 21 126.6 6.2 (4.9%) 3595 104.7 (2.9%) 612 750 MP 500nL 6517 6650 1.02 19 84.5 9.1 (10.7%) 1142 66.8 (5.9%) 672 1000 MP 250nL 6466 6598 1.02 19 87.2 6.3 (7.3%) 1512 136.2 (4.7%) 681 750

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23 Figure 1. 10. PS 6 direct comparison of resolved M/Z peaks for Induction Based Fluidics (IBF) and micropipette (MP) at selected volumes (nL). Figure 1. 11 MALDI Spectra (Raw Signal) PS 6 Induction Based Fluidics (IBF) 250nL deposition.

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24 1.3.1.4 PS (92,600 Da), TPB, AgTFA: (PS 92) Table 1. 5 summarizes data for PS 92 obtained from MALDI for IBF and micropipette depositions. Included in this table are S/N, intensity at M P, R s and P SP PS 92 data in T able 1. 2 reveals that the IBF deposition (100nL) had increas ed S/N and intensity over MP. IBF increased S/N by 190% and intensity by 128%. P SP obtained from the IBF enhanced signal pr oducing 14 more monomer units in the FWHM. Figure 1. 12 graphically represents the overall signal intensity improvement provided by the IBF deposition method for PS 92. Figure 1. 13 shows the raw MALDI spectra obtained for the PS 92 IB F deposition volume of 100nL.

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25 Table 1.5 Polystyrene(92,600 Da), TPB, AgTFA (PS 92) characterization data. (@ M P ) Laser Shots PS 92 M N M W PD P SP (S/N) (S/N) (RSD%) Intensity (RSD%) Rs IBF 100nL 92630 92801 1.00 40 26.1 0.32 ( 1.23%) 89 2.12 (2.36%) 14 750 MP 100nL 92532 92727 1.00 30 9 0.70 (7.83%) 39 2.0 (5.13%) 14 750

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26 Figure 1. 12 Polystyrene 92,600 (Da) (PS 92) direct comparison of signal intensity for resolved M/Z peaks for Induction Based Fluidics (IBF) and micropipette (MP) at 100nL. Figure 1. 13 Polystyrene 92,600 (Da) (Raw Signal) PS 92 Induction Based Fluidics (IBF) 100nL deposition

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27 1.3.2 Poly(methyl methacrylate) 1. 3.2 1 PMM A (10,600 Da), DHB, NaTFA: (PMMA 10.6 ) Table 1. 6 summarizes data for PMMA 10.6 obtained from MALDI. Included in th is table are S/N and intensity. Table 1. 2 shows the percent increase obtained with the IBF method in volume to volume comparisons. IBF increased S/N by 140% and intensity 55% at 500nL. IBF also increased S/N by 103% and intensity by 115% at 250nL.

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28 Table 1.6. Poly(methyl methacrylate) 10,600 (Da), DHB, NaTFA. (PMMA 10.6) characterization data. (@ M P ) Laser Shots PMMA 10.6 (S/N) (S/N) (RSD%) Intensity (RSD%) IBF 500nL 12 0.1 (0.83%) 1960 92.6 (4.7%) 1000 IBF 250nL 11.8 0.15 (1.3%) 3450 106.4 (3.1%) 750 MP 500nL 5 0.55 (10.5%) 1260 85.3 (6.8%) 1000 MP 250nL 5.8 1.3 (22.4%) 1598 46.5 (2.9%) 750

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29 1. 3.3 Poly( ethylene glycol) 1 .3 .3. 1 PEG (5000 Da), Dithranol, NaTFA : ( PEG 5 ) Table 1. 7 summarizes all the data for PEG 5 obtained from MALDI. Included in this table are M n M w PD, P SP S/N, R s at modal M p laser shots, and intensity. Data in T able 1. 2 lists the percent change in volume to volume compar isons of IBF and MP for PEG 5. IBF showed an i ncrease in S/N and Intensity. The most dramatic increase was obtained at 500nL where IBF showed a gain in of S/N o f 660% and intensity of 166%. It should be noted tha t with increasing volume, IBF yielded enhanced characteristics when compared to micropipette depositions, contrary to previous mentioned data. This observation of both increased S/N and R S at larger volumes is also counter intuitive to what has been obser ved in literature [5, 9, 10] and may be due to decreased analyte segregation due to the induced electric filed [14, 15, 25 30]. PEG 5 analysis can show the importance to the use of P SP when determining the polymer spread. The PD values for PEG 5 that wer e generated from the two depositional methods are statistically identical. The P SP method is able to distinguish a difference between the IBF and micropipette depositions while the polydispersisty (PD) method reveals no discernable difference. The compar ison of the IBF and micropipette depositions at 500nL reveal that there was a decrease in P SP of 15 less monomer repeat units within the FWHM of the M P Figure 1. 14 shows overall signal intensity improvement provided by the IBF deposition met hod for PEG 5 Figure 1. 15 shows the raw MALDI spectra obtained for the optimum PEG 5 IBF deposition volume of 500nL.

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30 Table 1.7 Poly(ethylene glycol) (5000 Da), Dithranol, NaTFA (PEG 5) characterization data. (@ M P ) Laser Shots (PEG 5) M N M W PD P SP (S/N) (S/N) (RSD%) Intensity (RSD%) Rs IBF 500nL 5378 5418 1.007 26 95 0.96 (1.01%) 3175 70.4 (2.2%) 1345 1000 IBF 250nL 5375 5418 1.008 31 28.3 3.3 (11.7%) 1631.5 41.3 (2.5%) 387 750 IBF 100nL 5376 5419 1.008 32 30.1 0.9 (3.0%) 1788 49.0 (2.7%) 451 750 SP 100nL 5069 5126 1.011 38 12.4 3.1 (24.9%) 1529 49.9 (3.3%) 579 750 MP 250nL 5174 5216 1.008 38 18.6 3.7 (19.6%) 1381 71.9 (5.2%) 602 750 MP 500nL 5099 5164 1.013 41 12.5 1.6 (12.8%) 1192 75.8 (5.2%) 334 1000

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31 F igure 1. 14 PEG 5 direct comparison of signal intensity for resolved M/Z peaks for Induction Based Fluidics (IBF), micropipette (MP) & Syringe pump (SP) at selected volumes (nL). Figure 1. 15 MALDI Spectra (Raw Signal) PEG 5 Induction Based Fluidics (IBF) 500nL deposition

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32 1.3.2 Deposition Morphology 1.3.2.1 Amorphous Polymer Sample Morphology With consistent results showing IBF depositions that yield significant increases in signal quality, our focus turned to the morphology of the deposition. When amorphous polymers are mixed with the crystalline matrix, deposited and drie d, the matrix recrystallizes. The extent to which the polymer associates with the matrix influences the quality of the MALDI spectra. Two trends appear when looking at the deposi tions made with amorphous polymers: (1) IBF depositions yielded larger crystal depositions; (2) IBF depositions having the same volume and concentration when compared to their MP counterparts were more compact occupying less physical surface area on both the steel AB MALDI plate and glass slides. As previously mentioned, studies have shown and promoted that smaller homogenous crystallization as the preferred and most productive morphology that renders quality MALDI signals [31 33]. In this study, we pre sent evidence from cross polarization microscopy that directly contradicts the commonly held belief that only smaller homogenous crystals produce quality signal. This contradiction is apparent in the amorphous polymer samples; PS 2 RA, PS 2, PS 92, and PM MA 10.6. Amorphous samples deposited with micropipette were observed to have smaller homogenous central areas with an outer ring that has different usually larger crystallization outcrops. This dichotomy seen in the micropipette depositions lends the samp le to become heterogeneous and ultimately non favorable for high qua lity spectra. W hen observing these images shown here, in th e reflected cross polar mode, please note and not confuse the fact that the MALDI plate itself also contains a ring that is engraved into the steel plate that appears in some sample photos as a dark scribed ring

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33 s equential numbers for sample recognition. The substrate effect has been known to change morphology and Tm of polymers based upon the affinity of the polymer to substrate [43] This effect was considered when taking cross polarization i mages on both glass and steel. The same morphological differences aforementioned between IBF and MP methods were noticed on both substra tes. This investigation used glass substrate to obtain cross polar transmission images to more clearly depict what was similarly observed on the AB Steel MALDI target. 1.3.2. 2 Semi Crystalline Polymer Sample Morphology PEG 5 is the only MALDI TOF sample t ested here that is semi crystalline. This quality may explain why PEG 5 follows a different trend in depositional comparisons. The semi crystalline PEG 5 yielded two trends: (1) IBF depositions showed uniquely smaller homogenous crystallization; (2) IBF depositions continued to present more compact depositions. 1.3.2. 3 Depositional Spatial C oncentration All depositions were more spatially concentra ted when deposited via IBF. Clarifying that in volume to volume comparisons of MP and IBF less planar surface area was occupied when IBF deposit ional technology was employed. Table s 1. 8 ( a e ) show 2 ) of IBF and MP. Table 1. 9 gives percent reduction of IBF deposits across volume and sample type. The approximate average reduction in spatial area is about 40% throughout all samples tested of equal volume As expected there is variance between MALDI TOF recipes that address more complicated interaction s yet still lead to a reduction in spatial area fr om ca. 23 to 70

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34 percent. Approximately, 1.5x to f or all depositions using IBF. Table 1.8(a). PS RA 2 2 ) of IBF and MP depositions. PS RA 2 (nL) RSD Area 2 ) IBF 500 1050 18 1.70% 3.46 IBF 250 1025 16.1 1.60% 3.3 IBF 100 875 13.5 1.50% 2.41 MP 500 1550 35.3 2.30% 7.55 MP 250 1250 30 2.40% 4.91 MP 100 1000 28.4 2.80% 3.14 Table 1.8(b). PS 2 ) of IBF and MP depositions. PS 2 (nL) RSD 2 ) IBF 500 1150 17 1.50% 4.15 IBF 250 875 14.8 1.70% 2.41 IBF 100 550 11.7 2.10% 0.95 MP 500 1500 32.1 2.10% 7.07 MP 250 1150 28.1 2.40% 4.15 MP 100 1000 26.2 2.60% 3.14 Table 1.8(c). PS 2 ) of IBF and MP depositions. PS 92 (nL) RSD 2 ) IBF 100 625 11.3 1.80% 1.23 MP 100 1000 34.8 3.50% 3.14

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35 Table 1.8(d). PMMA 2 ) of IBF and MP depositions. PMMA 10.6 (nL) RSD 2 ) IBF 500 1000 17.4 1.70% 3.14 IBF 250 900 14.7 1.60% 2.54 IBF 100 650 12.7 2.00% 1.33 MP 500 1300 40.7 3.10% 5.31 MP 250 1100 29.8 2.70% 3.8 MP 100 750 30.1 4.00% 1.77 Table 1.8(e). PEG 2 ) of IBF and MP depositions. PEG 5 (nL) RSD 2 ) IBF 500 1550 55.1 3.60% 7.55 IBF 250 1125 33.5 3.00% 3.98 IBF 100 800 31.1 3.90% 2.01 MP 500 2125 73.8 3.50% 14.19 MP 250 1600 52 3.30% 8.04 MP 100 1100 43.1 3.90% 3.8

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36 2 ) reduction in percent of the IBF depositions when compared to micropipette depositions of equal volume and analyte. PS 2 RA PS 2 PS 92 PMMA 10.6 PEG 5 AVG SD IBF 500 54% 41% -41% 53% 47% 7.3% IBF 250 33% 42% -33% 49% 39% 8.01% IBF 100 23% 70% 61% 25% 53% 46% 21.15% AVG 37% 51% 61% 33% 52% SD 15.7% 16.2% (n/a) 8.0% 2.1%

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37 1.3.3 Cross Polarization Images 1.3.3.1 PS (2300 Da), RA, AgTFA: (PS 2 RA) Figure 1 .16 shows cross polarization images obtained in transmission and reflected mode for PS 2 RA. The different substrates (glass and steel) for the two imaging methods (transmission and reflection) show slight differences in area occupied. These differences stem from the hyprophillicity/hydrophobicity differences of each surface. Both substrates though different display the same macro trends previously o utlined. When observing the sample presented here please note that the Z direction, sample elevation, could no t be simultaneously focused. The darker central crystalline areas in Figure 1.16 (IB F 250 and 500nL ), reflection mode, represent a stacking of the same large cryst als as seen in the periphery. The IBF 100 to 500 nL (transmission mode on glass substrate) allows for more light to pass through the sample better revealing the homogenous large crystalline formations in the center that were obscured from view in reflec tion mode (steel substrate). In comparison it can be seen that IBF depositions produce larger crystals over micropipette counterparts on both applied substrates. Finally, the ave rage reduction in planar area occupied by IBF depositions show ca. 23% to 54% for the volumes observed, Table 1. 9 1.3.3.2 PS (2300 Da), TPB, AgTFA: (PS 2) Figure 1.17 allows for the comparison of IBF and micropipette deposition on glass and steel plate using cross polarization microscopy of the PS 2 recipe In Figure 1.17 larger crystal formations are observed with IBF depositions. Again the spatial concentration was greater in depositions using IBF versus MP for volume 100 to 500nL Using TPB as a matrix leads to different crystallization morphology while still following

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38 the trends of smaller depositional area and larger more homogeneous distribution using IBF. Here the undesirable heterogeneous outer ring, also known as the cup ring effect can be seen distinctly in MP depositions [25, 36, 38, 44] These highly v aried areas in MP depositions are the cause for the high variance in MALDI TOF spectra intensity and S/N IBF depositions are more homogenous and contain large r crystal formations than the ir MP counterparts. The IBF method reduced the spatial are a occupi ed from 41% to 70% depending upon depositional volume, Table 1. 9 1.3.3.3 PS (92,600 Da), RA, AgTFA: (PS 92 RA) Figure 1.18 shows comparison of IBF and micropipette deposition on glass and steel plate using cross polarization microscopy of the PS 92 RA recipe. Note that this recipe was not processed using MALDI TOF, but this was undertaken to observe what an increase in molar mass of the polymer standard from 2,300 Da. to 92,000 would have upon the IBF depositional method morphology In Figure 1.18, cross polarization clearly outline s that with this recipe much larger crystal structures are generated. The crystals are in fac t even more pronounced when compared to the PS 2 RA sample. Since the only difference is the molar mass of the polymer in the MALDI recipe tested the observed dramatic increase in large crystallization using IBF may be due to the greater molar mass of the polymer standard. This additional mass may provide beneficial nucleation environm ents to promote crystallization, an observance that only occurs with the IBF device deposited samples. 1.3.3.4 PS (92,600 Da), TPB, AgTFA: (PS 92) Figure 1.19 shows the cross polarization images obtained in transmission and reflected mode for PS 2 100nL depositions Comparing the two methods reveals that IBF has ca. 61% reduction of depositional density for reflection (steel plate) Table 1. 9

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39 IBF shows great er density per unit area over micropipette for PS 92 samples along with larger crystal formation. seen in the MP depositions while the trend continues to be seen that larger crystallizatio n and more homogeneous distributions are being observed using IBF 1.3.3.5 PMMA (10,600 Da), DHB, NaTFA: ( PMMA 10.6 ) Cross polarization images of PMMA 10.6 show a difference in homogeneity for PMMA 10.6 depositions made by micropipette, Figure 1.20. IB F cross polarization images reveal homogenous crystalline depositions that exhibit greater compactness having 25% to 41% reduction in occupied area, Table 1. 9 The optimum deposition volume for PMMA 10.6 was 500nL for both IBF and micropipette yielding the best S/N for each deposition method. The IBF and micropipette 500nL depositions both show homogenous crystallization. When the micropipette 500nL deposition is directly compared to IBF 500nL it is clear that the IBF has greater crystal density per unit area, ca. 1.7x greater crystal density. A video comparison of the real time IBF versus micropipette crystallization morphology of PMMA 10.66 at 25, 75, 100, 15 0, 200, 250, 500, 1000 nL for IBF and 100, 250, 500nL, for micropipette is available on the World Wide Web at http://chemistry.usf.edu/faculty/harmon/ Synthetic Polymer/Matrix Crystallization Video (Windows Media) 1.3.3.6 PEG (5000 Da), Dithranol, NaTFA: ( PEG 5 ) PEG 5 IBF depositions showed uniquely smaller homogenous crystallization w hile still maintain ing greater spatial density over MP depositions of equal volume MP

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40 PEG 5 samples also have shown a large heterogeneous feather like ring out cropping where these were not apparent in IBF depositions Figure 1.21. The PEG 5 500nL deposition s had the greatest increase in intensity and S/N This deposited volume was ca. 1.8x greater crystal den sity representing a 53% reduction in planar area occupied, Table 1. 9.

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41 PS RA AgTFA 100nL 250nL 500nL 100nL IBF (transmission) 250nL IBF (transmission) 500nL IBF (transmission) 100nL micropipette (transmission) 250nL micropipette (transmission) 500nL micropipette (transmission) 100nL IBF (reflection) 250nL IBF (reflection) 500nL IBF (reflection) 100nL micropipette (reflection) 250nL micropipette (reflection) 500nL micropipette (reflection) Figure 1.16 Polystyrene (2300 Da.) retinoic acid, AgTFA cross polarization images in transmission (top) and reflected (bottom) for IBF and micropipette 100 to 500 nL depositions.

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42 PS2 TPB AgTFA 100nL 250nL 500nL 100nL IBF (transmission) 250nL IBF (transmission) 500nL IBF (transmission) 100nL micropipette (transmission) 250nL micropipette (transmission) 500nL micropipette (transmission) 100nL IBF (reflection) 250nL IBF (reflection) 500nL IBF (reflection) 100nL micropipette (reflection) 250nL micropipette (reflection) 500nL micropipette (reflection) Figure 1.17 Polystyrene (2300 Da.), tetrap henyl butadiene, AgTFA cross polarization images in transmission (top) and reflected (bottom) for IBF and micropipette 100 to 500 nL depositions.

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43 PS 92 RA AgTFA 100nL 250nL 500nL 100nL IBF (transmission) 250nL IBF (transmission) 500nL IBF (transmission) 100nL micropipette (transmission) 250nL micropipette (transmission) 500nL micropipette (transmission) 100nL IBF (reflection) 250nL (reflection) 500nL IBF (reflection) 100nL micropipette (reflection) 250nL micropipette (reflection) 500nL micropipette (reflection) Figure 1.18. Polystyrene (92,600 Da.), retinoic acid, AgTFA cross polarization images in transmission (top) and reflected (bottom) for IBF and micropipette 100 to 500 nL depositions

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44 PS 92 RA AgTFA Transmission Reflection 100nL IBF 100nL IBF 100nL micropipette 100nL micropipette Figure 1.19 Polystyrene (92,600 Da.), tetraphenyl butadiene, AgTFA ) cross polarization images in transmission (left) and reflected (right) for IBF and micropipette nL depositions.

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45 PMMA DHB NaTFA 100nL 250nL 500nL 100nL IBF (transmission) 250nL IBF (transmission) 500nL IBF (transmission) 100nL micropipette (transmission) 250nL micropipette (transmission) 500nL micropipette (transmission) 100nL IBF (reflection) 250nL IBF (reflection) 500nL IBF (reflection) 100nL micropipette (reflection) 250nL micropipette (reflection) 500nL micropipette (reflection) Figure 1.20 Poly(methyl methacrylate) (10,600 Da.), dihydroxy benzoic acid, NaTFA cross polarization images in transmission (top) and reflected (bottom) for IBF and micropipette 100 to 500 nL depositions.

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46 PEG5 Ditranol NaTFA 100nL 250nL 500nL 100nL IBF (transmission) 250nL IBF (transmission) 500nL IBF (transmission) 100nL micropipette (transmission) 250nL micropipette (transmission) 500nL micropipette (transmission) 100nL IBF (reflection) 250nL IBF (reflected) 500nL IBF (reflection) 100nL micropipette (reflection) 250nL micropipette (reflection) 500nL micropipette (reflection) Figure 1.21 Poly(ethylene glycol) (5,000 Da.), dithranol NaTFA cross polarization images in transmission (top) and reflected (bottom) for IBF and micropipette 100 to 500 nL depositions.

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47 1. 4 Conclusio n Analysis of synthetic polymers using MALDI, mass range 2,500 Da to 92,000 Da, can benefit from using nanoliter IBF method for sample preparation. This benefit translates over a wide variety of polymers and ion sources. This sample preparation method show s greater compactness and homogeneity of sample deposition. With these three polymer standards (PS PMMA PEG) we have seen improvements in S/N up to 660% and increases in s ignal intensity up to 438%. Furthermore, additional MALDI work should be undertake n to investigate the benefit R S from IBF focusing on resolved isotope clusters in reflectron mode. This device may provide a simple platform to standardize sample preparation, reducing analyst errors while increasing the signal quality. This could lead to increased precision and accuracy when investigations are conducted using MALDI. Additionally, th is method may improve inter laboratory comparisons as a result of removing operator bias at the sample preparation step. Cross polar microscopy has shown different morphology between IBF and micropipette depositions. These dramatic differences seen betwe en IBF and micropipette depositions require further study for assessment. Investigations into these differences are underway. Three attractive ideas for these morphological variances are proposed so far: (1) dissimilar rates of evaporation, (2) thickness of deposition, or (3)

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48 Additionally, dramatic morphological differences between IBF and micropipette were captured in real time movie images. These ima ges are available for viewing on the World Wide Web at http://chemistry.usf.edu/faculty/harmon/ Synthetic Polymer/Matrix Crystallization Video (Windows Media) We forward that IBF nanoliter depositions increase the spatial concentration of analyte compared to L depositions and hence increase the density of hot spots. This also quite naturally minimizes the area where there is no analyte or cold spots, that can only generate large cluster or other ions that destroy (neutralize) the analy tical ion of interest. We further speculate that as nanoliter depositions show improved crystal morphology and no ring structure, evidence of increased solubility, that IBF nanoliter As such, i t is proposed that a confluence of factors can be invoked to explain the fact that nL IBF depositions have been observed to increase signal and noise in positive ion data shown here. 1.5 Acknowledgements We would like to extend our thanks to National Insti tute of Standards and Technology (NIST) Polymers division Gaithersburg, MD USA for providing us with polymer standards for use in this research opportunity. Special thanks to Dr. John M. Koomen Scientific Director, Proteomics Core Facility at H. Lee Moffi t Cancer Center & Research Institute for allowing use of the Voyager Workstation.

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49 1.6 References 1. Odian G. Principals of Polymerization Hoboken, NJ: John Wiley & Sons, Inc. 2004. 2. Montaudo G, Samperi F, and Montaudo MS Progress in Polymer Science 2006;31(3):277 357. 3. Nielen MW Mass Spectrometry Reviews 1999;18(5):309 344. 4. Tatro SR, Baker GR, Fleming R, and Harmon JP Polymer 2002;43(8):2329 2335. 5. Bahr U, Deppe A, Karas M, Hillenkamp F, and Giessmann U Analytical Chemistry 1992;64(22):2866 2869. 6. Collins EA, Bares J, and Billmeyer FW. Experiments in Polymer Science New York John Wiley & Sons 1973. 7. Woldegiorgis A, Lwenhielm P, Bjrk A, and Roeraade J Rapid Communica tions in Mass Spectrometry 2004;18(23):2904 2912. 8. Basile F, Kassalainen GE, and Williams SKR Analytical Chemistry 2005;77(9):3008 3012. 9. Shahgholi M, Garcia BA, Chiu NHL, Heaney PJ, and Tang K Nucleic Acids Research 2001;29(19):art. no. e91. 10. Trimpin S and McEwen CN Journal of the American Society for Mass Spectrometry 2007;18(3):377 381. 11. Little DP, Cornish TJ, Odonnell MJ, Braun A, Cotter RJ, and Koster H Analytical Chemistry 1997;69(22):4540 4546. 12. Hung KC, Rashidzadeh H, Wang Y, a nd Guo BC Analytical Chemistry 1998;70(14):3088 3093. 13. Kussmann M, Nordhoff E, RahbekNielsen H, Haebel S, RosselLarsen M, Jakobsen L, Gobom J, Mirgorodskaya E, KrollKristensen A, Palm L, and Roepstorff P Journal of Mass Spectrometry 1997;32(6):593 60 1. 14. Miliotis T, Kjellstrm S, Nilsson J, Laurell T, Edholm LE, and Marko Varga G Rapid Communications in Mass Spectrometry 2002;16(2):117 126. 15. Tu T, Sauter Jr AD, Sauter 3rd AD, and Gross ML Journal of the American Society for Mass Spectrometry 2008;19(8):1086 1090. 16. Sauter AD. Precise Electrokinetic Delivery of Minute Volumes of Liquid(s). In: Patent US, editor., vol. 6,149,815. USA, 2001.

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50 17. Sauter Jr AD American Laboratory 2007;39(3):22 29. 18. Clayton LM, Knudsen B, Cinke M, Meyyappan M, and Harmon JP J. Nanosci. Nanotech. 2007;7(10):3572 3579. 19. Mohomed K, Moussy F, and Harmon JP Polymer 2006;47(11):3856 3865. 20. Mohomed K, Gerasimov TG, Moussy F, and Harmon JP Polymer 2005;46(11):3847 3855. 21. Tatro SR, Baker GR, Bisht K, and Harmon JP Polymer 2003;44(1):167 176. 22. Emran SK, Liu Y, Newkome GR, and Harmon JP Journal of Polymer Science Part B Polymer Physics 2001;39(12):1381 1393. 23. Emran SK, Newkome GR, Weis CD, and Harmon JP Journal of Polymer Science Part B: Polym er Physics 1999;37(16):2025 2038. 24. Bertolucci Patricia RH and Harmon Julie P. Dipole Dipole Interactions in Controlled Refractive Index Polymers. Photonic and Optoelectronic Polymers, vol. 672: American Chemical Society, 1997. pp. 79 97. 25. Hoteling AJ, Erb WJ, Tyson RJ, and Owens KG Analytical Chemistry 2004;76(17):5157 5164. 26. Hanton SD and Owens KG Journal of the American Society for Mass Spectrometry 2005;16(7):1172 1180. 27. Debye P and Kleboth K Journal of Chemical Physics 1965;42(9):3155 &. 28. Wirtz D and Fuller GG Physical Review Letters 1993;71(14):2236 2239. 29. Wirtz D, Berend K, and Fuller GG Macromolecules 1992;25(26):7234 7246. 30. Lee JS, Prabu AA, Kim KJ, and Park C Macromolecules 2008;41(10):3598 3604. 31. Shimada T Thin Solid Films 2006;515(4):1568 1572. 32. Onuki A Europhysics Letters 1995;29(8):611 616. 33. Wetzel SJ, Guttman CM, and Flynn KM Rapid Communications in Mass Spectrometry 2004;18(10):1139 1146. 34. Snovida SI, Rak Banville JM, and Perreault H Jou rnal of the American Society for Mass Spectrometry 2008;19(8):1138 1146. 35. Leica. Polarization of Light. Leica Polarization of light RvF Booklet http://www.leica microsystems.com

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51 36. Hanton SD, Hyder IZ, Stets JR, Owens KG, Blair WR, Guttman CM, and Giuseppetti AA Journal of the American Society for Mass Spectrometry 2004;15(2):168 179. 37. Guttman CM, Wetzel SJ, Flynn KM, Fanconi BM, VanderHart DL, and Wallace WE Analytical Chemistry 2005;77(14):4539 4 548. 38. Wetzel SJ, Guttman CM, Flynn KM, and Filliben JJ. The Optimization of MALDI TOF MS for Synthetic Polymer Characterization by Factorial Design. Proceedings of the 52nd ASMS Conference on Mass Spectrometry and Allied Topics: Nashville, TN, 2004. 3 9. Karas M, Gluckmann M, and Schafer J Journal of Mass Spectrometry 2000;35(1):1 12. 40. Dou J, Shang W, and Chen Z Applied Surface Science 2004;236(1 4):57 62. 41. Sha YH, Zhang F, Li S, Gao XY, Xu JZ, and Zuo L Journal of Materials Science & Technol ogy 2004;20(3):253 256. 42. Pash H and Schrepp W. MALDI TOF Mass Spectrometry of Synthetic Polymers. New York: Springer Verlag, 2005. 43. Wang Y, Rafailovich M, Sokolov J, Gersappe D, Araki T, Zou Y, Kilcoyne ADL, Ade H, Marom G, and Lustiger A Physical Review Letters 2006;96(2):028303. 44. McLaughlin ML. Personal Communication. University of South Florida. Tampa, FL, 2010.

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52 CHAPTER 2 : THE MEASUREMENT OF CHARGE FOR INDUCTION BASED FLUIDIC MALDI DISPENSE EVENT AND NANOLITER VOLUME VERIFICATION IN REAL TIME 2.1 Introduction Herein we used an IBF nanoliter, microliter syringe [1, 2] In IBF, a charge is induced on the liquid by passing the fluid through an electric field [3, 4] inductively, not conductively as in electrospray ionization (ESI). In IBF there are no faradaic processes, only capacitance based ones, unlike ESI. The physics behind IBF reveals [3, 4] that unlike piezoelectric, sound, or any other technologies that are applied to transp ort liquids at low volumes, IBF kinetica lly launches drops to targets, as it dynamically directs the liquids to targets, and as we show here measures them on arrival, in real time. One major IBF application, nanoliter depositions for the production of Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI) plates, has been shown to increases in signal to noise ratios for Bradykinin measurements 10 fold and analysis precision, as well [5] Nanoliter IBF depositions also produce a major increase in MALDI sensitivity and reproducibility for synthetic polymers [6] (PMMA, PEG, and PS) even with polymers with M n ater than 90,000 u. Yergey has also observed up to a 100 fold increase in analysis sensitivity [7] for a major class of proteins, tubulins. These and similar observations on the analy [ 5] show significant imp rovement (ca. increases of 5 to 100 fol d) in sensitivity and a 3 to 20x percent in

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53 reproducibility using nanoliter IBF depositions for proteins, peptides and synthetic pol ymers. These enhancements in a wide range of molecules and mass ranges in both positive ion reflectron mode and negative ion linear mode, indicate that nL IBF deposition improves sensitivity across many MALDI applications. The ability to verify a dispense event and its magnitude in rea l time may aid quantitative quality control on MALDI measurements whether they are produced on a one at a time basis or via high throughput applications on robotic systems. IBF has many mass spectrometry ( MS ) and non MS applications because the simple tec hnique can be appended to common laboratory devices that are used for routine nanoliter sample handling from syringes, pipettes, chips, pumps and other fluid movement devices including tissue and LC/MALDI devices. The ability to accurately measure and to verify the volume deposited per event by IBF in real time could further aid the ability to QC and to improve MALDI quantitation. The ability to easily manipulate small volume solvents or solutes to targets also has applications in the areas of green chemi stry and in biological MALDI with limited sample sizes [5] Applications of nL IBF exist in non touch dispensing ( L, nL and pL), in parallel LC/MALDI, in defense homeland security [8] chemistry, for desorption electrospray ioization/direct analysis in real time ( DESI/DART ) standardization and applications [9] DNA/RNA sample preparation [10] and in TLC applications [11] With IBF nanoliter quantities of viscous liquid, human serum or whole human blood can be flown to MALDI targets. Furthermore IBF presents a second major application; a novel method of polymer electret synthesis This is herein investigated using 2 hydroxyethyl methacrylate (2 HEMA) An electret is a dielectric material that maintains a permanent electric charge or dipole polarization [12] Typically electrets can be produced by subjecting a dielectric material to corona or electron beam charging, placing in a n

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54 electric polin g field (ferroelectrically), using heat to modify crystal structure (pyroelectrically) and even by mobile ion transfer using surface contact (van der graaf) [12 14] Electrets have shown broad technological applications. Electret powder s have been made to selectively adhere to targeted substrates, as in xerography [13] Electret materials have found use in separations as coal is isolated from various impurities. Micro phones have utilized electrets to convert acoustical vibrations into electrical signals, removing the need for a n external power source in certain instances. Recently, investigations into electret self assembly to design novel materials have been of inter est [12, 13] Herein IBF has a unique place to provide mono disperse nL sized spherical electrets from a wide variety of materials. To explain IBF, in a flowing or stop flow laminar system, the volume dispensed is described by the Hagen Poiseuille equation, E q. 2. 1 [15] ( Eq. 2. 1) This law states that the volume of fluid ( V ) that flows down a small diameter capillary tube per unit of time ( t ) is proportional to the fourth power of the radius of the tube ( r ) the pressure pushing the fluid down the tube ( P ) and it is inversely proportional to the length of the tube ( l ) and the viscosity of the fluid Drople ts produced can be placed in an electric field, and become inductively energized. In these near perfect spheres the charge exists primarily on the surfaces [16, 17] The nanoliter device

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55 creates an exact volume mechanically in one mode. Purely electrokinetic IBF opera tion is also possible but it is not addresse d here. W hen a droplet is placed in an electric field ( E ) the droplet becomes charged, (q) and it experiences a force (F) [18] E q. 2 2 F = qE (E q. 2 2 ) This forc e launches the drop to a target with excellent accuracy and precision in a manner analogous to that used by Millikan [19] in his work determining the charge of the electron. This force is the same fo rce used in mass spectrometers to accelerate and focus ga s phase ions in a vacuum. Like gas phase ions, charged drops can be accelerated and directed in a dynamic manner to tar gets producing useful results. Further details are beyond the scope presented here and readers are directed to r efer previous work by Sauter or Amster for a more complete discussion [4, 20, 21] as Eq. 2. 3 [22] : q = k SA (E q. 2. 3) The charge on a drop (q) is proportional to the surface area (SA) with constant ( k ) The volume (V) relationships for a sphere of radius, r, are shown below. The measurements of the charge on drops produced by the IBF dispensing device at high potential were performed. Where Eq 2. 4 shows the equation for the volume of a sphere and Eq. 2. 5 is the relationship of SA of a sphere being followed by the relationship SA has to V Eq. 2. 6.

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56 3 (E q 2. 4) 2 (E q. 2. 5) 2 ) 2/3 (E q. 2 6) 2. 2 Experimental 2. 2 .1 Reagents and Materials NaCl and 12M hydrochloric acid were purchased from Fischer Chemicals in Fair Lawn, New Jersey USA Purified 2 Hydroxyethyl methacrylate (2 HEMA) was donated by Be nz Research and Development in Sarasota, FL Figure 2 1(a) 2 Hydroxy 2 methyl 1 phenyl 1 propanone (Benacure TM 1153) purchased from Mayzo Suwanee, Georgia, USA and used as received Figure 2. 1(b) Figure 2. 1. Rea gents. (a) 2 Hydroxyethyl methacrylate. (b) 2 Hydroxy 2 methyl 1 phenyl 1 propanone. 2.2.2 Charge Measurement Apparatus and Procedure The Nanoliter LLC IBF device Figure 1. 3 was connected to a programmable controller. The power was provided by an induction unit, and controlled a progra mmable laser machined inductor.

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57 was inserted using treated needles 20 cm long, havi ng A Keithley 6514 programmable electrometer ( Cleveland, Ohio, USA) was set to measure in nanocoulombs (nC) using a copper triaxial cable. A copper faraday cup, designed by the University of South Florida, with dimensions 2cm x 1cm x 1cm measured electric potential between the droplet and earth groun d. A shielding apparatus for the syringe and cup was constructed with aluminum screen (1.5 cm mesh). Additional electromagnetic (EM) shielding in addition to the faraday cage was employed due to the large electromagnetic frequency (EMF) output produced a t the IBF inductor when under power. Figure 2. 2( a ) sho ws aluminum mesh approximately 5 x 8 cm placed below the inductor unit of the IBF unit. This shield was grounded to an earthen groun d. An aluminum mesh square 5 x 10 cm was placed approximately 9 cm below the IBF inductor unit and was not grounded, Figure 2. 2(b ) This mesh served primarily to reflect the EM F radiation created by the inductor which in effect inverts the IBF inductor EMF spectrum and reflects back EMF causing destructive interferenc e lowering EMF radiation. Wire mesh 25 x 25 cm, F igure 2. 2(c ) was placed on a ring to serve as a guide for the lengthy fused silica capillary needle holding the correct position above the faraday cage 8 x 6 x 5 cm Figure 2. 2(d ).

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58 Figure 2. 2. Induction Based Fluidics (IBF) charge measurement apparatus to shield electromagnetic frequency radiation (EMF) interference from sensitive faraday cup measurements (a ) Aluminu m mesh approximately 5 x 8 cm.(b ) Aluminum mesh square 5 x10 cm to reflect the EMF radiation.(c ) Wire mesh guide 25 x 25 cm.(d ) Faraday cage 8 x 6 x 5 cm. The electrometer was set to the nC mode. The copper was contact connected and completed electrical connections between the faraday cup, triaxial cable, and the electrometer, eliminating any charge capacitance build up from the near contact of two d c b a

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59 dissimilar metals [23] The faraday cup was suspended in mida ir, not in contact with the faraday cage. S ince the magnitude of induced charge on droplets dispensed into the faraday cup is very small and the energy is high, environmental electric fields affect the accuracy of the measured charge [23, 24] 2.2.3 Charge Measurement Solutions and Procedure NaCl and HCl solutions of 0.33M, 0.166M, 0.091M in D.I. H 2 O, and 2 hydroxyethyl methac rylate (2 HEMA) with 2.0wt% Bena cure TM 1153 photo initiator were launched into the Faraday cup. Four tria ls were conducted for each volume kinetically launched where volumes ranged from 11to 400 nL for electrolyte solutions and 37 to 400 nL for the monomer and initiator solution The rate of ambient charge build up was measured so that the ambient charge w as no greater than 0.001 nC/s. The mean standard deviation 2 ) were calculated for ea ch volume and concentration. The cup was grounded between each shot. 2.2.4 Electrets Apparatus and Procedure T o create electrets using 2 HEMA with 2.0wt% B en a cure TM 1153 t he IBF device was set atop fabricated environmental chamber Figure 2. 3. The environmental chamber contained a positive flow of N 2 to provide an inert environment to promote UV initiated radical chain polymerization. The apparatus shown in Figu r e 2. 3 allowed for the kinetic launch of 2 HEMA with 2.0wt% Bena cure TM 1153 solution onto a smooth surface block of frozen CO 2 (dry ice) freezing the droplet in a near perfect sphere. After the droplets were deposited atop the frozen CO 2 block they were translated under a UV Lamp of 254nm and kept UV irradiated until the frozen C O 2 was completely sublimed, approximately 2.5 hours.

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60 Figure 2. 3. E lectret manufacture apparatus using IBF and UV initiated polymerization of 2 HEMA with 2.0wt% Benacure atop frozen CO 2 2.3 Results and Data Analysis 2.3.1 Charge Measurements [25] model the surface area is used as the dependant variable in plots. Surface areas in pl ots of solutions ranged from 24 to 263 nm 2 (11 to 400nL). Figures 2. 4 (a c) and Figures 2. 5 (a c) s how charge measurements for HCl and NaCl at varied molarities respectively. Statistical data for

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61 IBF depositions is also provided in Table s 2. 1( a c ) and Table s 2. 2( a c ) for HCl and NaCl respectively. The experiments demonstrate a strongly correlated, potentially linear relationship between surface areas and charge on droplets, in agreement with previous studies [3, 17] a given liquid that ch arge can be used to verify the volume of IBF launched droplets at high potential. Figure 2. 4 (a).

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62 Figure 2. 4 (b). Figure 2. 4 (c). Figure 2. 4 Varied molar concentrations of HCl charge (nC) versus surface a rea (nm 2 ). (a) 0.33M HCl. (b) 0.166M HCl. (c) 0.091M HCl.

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63 Table 2.1(a). 0.33M HCl IBF charge depo sitional data for 11 to 400 nL. [0.33] HCl Volume nL 1 nC 2 nC 3 nC 4 nC 2 r (nm) SA (nm 2 ) 400.68 0.097 0.09 0.11 0.095 0.098 8.52E 03 7.27E 05 4.57 262.83 300.51 0.085 0.09 0.082 0.085 0.0855 3.32E 03 1.10E 05 4.16 216.97 200.34 0.07 0.07 0.075 0.08 0.07375 4.79E 03 2.29E 05 3.63 165.58 151.2 0.055 0.06 0.06 0.05 0.05625 4.79E 03 2.29E 05 3.30 137.25 100.17 0.04 0.05 0.051 0.05 0.04775 5.19E 03 2.69E 05 2.88 104.31 75.6 0.04 0.04 0.04 0.03 0.0375 5.00E 03 2.50E 05 2.62 86.46 37.8 0.03 0.02 0.03 0.02 0.025 5.77E 03 3.33E 05 2.08 54.47 20.79 0.03 0.03 0.03 0.04 0.0325 5.00E 03 2.50E 05 1.71 36.56 11.34 0.015 0.025 0.015 0.017 0.018 4.76E 03 2.27E 05 1.39 24.41 Table 2.1(b) 0.166M HCl IBF charge dep ositional data for 11 to 400 nL. [0.166] HCl Volume nL 1 nC 2 nC 3 nC 4 nC 2 r (nm) SA (nm 2 ) 400.68 0.08 0.08 0.09 0.09 0.085 5.77E 03 3.33E 05 4.57 262.83 300.51 0.07 0.08 0.08 0.08 0.0775 5.00E 03 2.50E 05 4.16 216.97 200.34 0.06 0.07 0.06 0.07 0.065 5.77E 03 3.33E 05 3.63 165.58 151.2 0.07 0.05 0.06 0.06 0.06 8.16E 03 6.67E 05 3.30 137.25 100.17 0.04 0.04 0.04 0.04 0.04 0 0 2.88 104.31 75.6 0.05 0.04 0.04 0.04 0.0425 5.00E 03 2.50E 05 2.62 86.46 37.8 0.03 0.03 0.03 0.02 0.0275 5.00E 03 2.50E 05 2.08 54.47 20.79 0.02 0.02 0.02 0.03 0.0225 5.00E 03 2.50E 05 1.71 36.56 11.34 0.013 0.02 0.02 0.02 0.0182 3.50E 03 1.23E 05 1.39 24.41

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64 Table 2. 1 (c) 0.091M HCl IBF charge depositional data for 11 to 400 nL. [0.091] HCl Volume nL 1 nC 2 nC 3 nC 4 nC 2 r (nm) SA (nm 2 ) 400.68 0.072 0.08 0.082 0.081 0.079 4.57E 03 2.09E 05 4.57 262.83 300.51 0.08 0.073 0.07 0.068 0.073 5.25E 03 2.76E 05 4.16 216.97 200.34 0.06 0.062 0.061 0.06 0.061 9.57E 04 9.17E 07 3.63 165.58 151.2 0.05 0.053 0.053 0.051 0.052 1.50E 03 2.25E 06 3.30 137.25 100.17 0.04 0.04 0.04 0.05 0.043 5.00E 03 2.50E 05 2.88 104.31 75.6 0.041 0.043 0.041 0.04 0.041 1.26E 03 1.58E 06 2.62 86.46 37.8 0.033 0.03 0.04 0.03 0.033 4.72E 03 2.23E 05 2.08 54.47 20.79 0.02 0.02 0.02 0.03 0.023 5.00E 03 2.50E 05 1.71 36.56 11.34 0.01 0.01 0.02 0.02 0.015 5.77E 03 3.33E 05 1.39 24.41

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65 Figure 2 5( a ). Figure 2 5( b )

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66 Figure 2. 5(c). Figure 2. 5. Varied molar concentrati ons of NaCl charge (nC) versus surface a rea (nm 2 ). (a) 0.33M NaCl.( b) 0.166M NaCl.(c) 0.091M NaCl.

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67 Table 2.2(a). 0.33M NaCl IBF charge depositional data for 11 to 400 nL. [0.33]NaCl Volume nL 1 nC 2 nC 3 nC 4 nC 2 r (nm) SA (nm 2 ) 400.68 0.1 0.09 0.09 0.09 0.0925 5.00E 03 2.50E 05 4.57 262.83 300.51 0.07 0.08 0.08 0.07 0.075 5.77E 03 3.33E 05 4.16 216.97 200.34 0.07 0.06 0.06 0.07 0.065 5.77E 03 3.33E 05 3.63 165.58 151.2 0.05 0.06 0.06 0.06 0.0575 5.00E 03 2.50E 05 3.30 137.25 100.17 0.05 0.05 0.05 0.05 0.05 0 0 2.88 104.31 75.6 0.04 0.04 0.05 0.04 0.0425 5.00E 03 2.50E 05 2.62 86.46 37.8 0.03 0.03 0.03 0.03 0.03 0 0 2.08 54.47 20.79 0.02 0.02 0.02 0.02 0.02 0 0 1.71 36.56 11.34 0.02 0.02 0.02 0.02 0.02 0 0 1.39 24.41 Table 2.2(b). 0.166M NaCl IBF charge depositional data for 11 to 400 nL. [0.166]NaCl Volume nL 1 nC 2 nC 3 nC 4 nC 2 r (nm) SA (nm 2 ) 400.68 0.08 0.08 0.08 0.07 0.078 5.00E 03 2.50E 05 4.57 262.83 300.51 0.07 0.07 0.08 0.07 0.073 5.00E 03 2.50E 05 4.16 216.97 200.34 0.05 0.06 0.06 0.06 0.058 5.00E 03 2.50E 05 3.63 165.58 151.2 0.05 0.05 0.05 0.05 0.050 0 0 3.30 137.25 100.17 0.05 0.04 0.04 0.03 0.040 8.16E 03 6.67E 05 2.88 104.31 75.6 0.04 0.05 03 0.04 0.043 5.77E 03 3.33E 05 2.62 86.46 37.8 0.03 0.03 0.03 0.03 0.030 0 0 2.08 54.47 20.79 0.02 0.01 0.03 0.03 0.023 9.57E 03 9.17E 05 1.71 36.56 11.34 0.02 0.02 0.02 0.02 0.020 0 0 1.39 24.41

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68 Table 2.2(c). 0.091M NaCl IBF charge depositional data for 11 to 400 nL. [0.091][NaCl] Volume nL 1 nC 2 nC 3 nC 4 nC 2 r (nm) SA (nm 2 ) 400.68 0.07 0.06 0.08 0.07 0.070 8.16E 03 6.67E 05 4.57 262.83 300.51 0.06 0.07 0.06 0.07 0.065 5.77E 03 3.33E 05 4.16 216.97 200.34 0.05 0.05 0.05 0.05 0.050 0 0 3.63 165.58 151.2 0.04 0.05 0.05 0.05 0.048 5.00E 03 2.50E 05 3.30 137.25 100.17 0.04 0.03 0.04 0.04 0.038 5.00E 03 2.50E 05 2.88 104.31 75.6 0.04 0.04 0.03 0.03 0.035 5.77E 03 3.33E 05 2.62 86.46 37.8 0.02 0.03 0.02 0.02 0.023 5.00E 03 2.50E 05 2.08 54.47 20.79 0.01 0.02 0.02 0.02 0.018 5.00E 03 2.50E 05 1.71 36.56 11.34 0.02 0.02 0.01 0.02 0.018 5.00E 03 2.50E 05 1.39 24.41

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69 Next we examined the surface charge upon an organic monomer 2 HEMA with 2.0wt% Beniacure TM 1153 photo initiator. Figure 2. 6 shows the results obtained for surface charge upon droplets 53 to 305 nm 2 (37 to 500 nL). Statistical data is shown in Table 2. 3 for 2 HEMA with 2.0wt% Benacure TM Again, t here is a high correlation of charge to surface areas observed. This data show s that b oth organic and electrolyte solution nL drops can be monitored via this technique. Figure 2. 6. 2 HEMA with 2.0wt% Benacure TM 1153 charge (nC) versus surface a rea (nm 2 )

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70 Table 2.3. 2 HEMA with 2.0wt% Benacure TM 1153 IBF charge depositional data for 11 to 400 nL. 2 HEMA with 2.0wt% Benacure 1153 Volume nL 1 nC 2 nC 3 nC 4 nC 2 r (nm) SA (nm 2 ) 400 0.89 0.83 0.79 0.9 0.853 5.19E 02 2.69E 03 4.57 262.54 300 0.73 0.79 0.83 0.84 0.798 4.99E 02 2.49E 03 4.15 216.72 200 0.55 0.59 0.68 0.77 0.648 9.81E 02 9.62E 03 3.63 165.39 151 0.44 0.62 0.44 0.59 0.523 9.60E 02 9.23E 03 3.30 137.13 100 0.32 0.52 0.49 0.49 0.455 9.11E 02 8.30E 03 2.88 104.19 75 0.35 0.22 0.33 0.33 0.308 5.91E 02 3.49E 03 2.62 86.01 37 0.32 0.17 0.36 0.15 0.250 1.06E 01 1.11E 02 2.07 53.70

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71 All nC v ersus surface area graphs show non zero intercepts which we interpret as being due to a charging mechanism other than being related to the drop surface volume. A number of potential sources can contribute to this; from air particulates to the indu ctive charging of the apparatus itself which may be the case here as the intercepts are numerically similar. The difficulty in measuring low currents at high energy are well known [26] These non zero intercepts are not surprising, but they of course limit the ultimate sensitivity of the technique to measure/verify volume deposition. We note that this prototype devic e was not optimized to limit EMF interference effects between the device and the sample. As such, the non zero inter cepts are not surprising. In Figures 2. 1 and Figures 2. 2 we had hoped to observe slopes related to sample concentrations. Rather, the charges, especially at the lowest volumes, were similar, irrespective of the liquid. In these cases we could measure di fferences within, but not between samples. We attribute that observation to the fact that these solutions are of high concentration where non ideal liquid solution behavior is common. It is also known that the thickness of the double layer whose formatio n is inferred in IBF, can shrink dramatically with increasing concentration, a phenomenon known as double layer compression. It is this property of the double layer that explains the fact that the slopes do not differ greatly, although at the highest volu mes the anticipate d order is observed for the mean values [27] 2.3.2 HEMA Electrets Using the same principals to measure the charge on the dispensed IBF droplets this study sought the target of synthesizing permanent polymer electrets and mea suring their permanent charge. Electrostatically c harge d droplets were reported by Sauter to be trapped in via freezing IBF kinetically dispensed EtOH onto dry ice [28] The EtOH

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72 frozen electret was repeated and confirmed in our lab at the University of South Florida where it is inte resting to note that the frozen droplets of EtOH electro statically repelled other frozen droplets kinetically launched within the vicinity, a t times providing a repulsion forc eful enough to scatter the frozen EtOH droplet some >10 cm away. Using 2 HEMA wit h a radical chain initiator, 2.0 wt% Benacure TM an IBF extension into polymer electret formation was undertaken. While the 2 HEMA droplet was to remain frozen atop the dry ice a UV lamp of 254 nm was set to irradiate the 2 HEMA droplets to polymerize. It was intended that the permanent surface charge consisting of the electret double layer would remain in place creating a permanent electros tatic electret. Minimal success was obtained in this experiment. Only ca. 28% of the frozen 2 HEMA droplets manag ed to survive the polymerization atop the subliming dry ice. Figure s 2. 7( a c ) show successfully synthesized near perfect spherical nano liter volume droplets. Figure 2. 7. P oly(2 HEMA) IBF dispensed droplets. (a) 200 nL poly(2 HEMA) 60x magnification ( b) 180 nL poly(2 HEMA) with Atracid Blue FG dye 100x magnification (c) 128 nL poly(2 HEMA) with Allura Red AC dye 100x magnification. Using the Faraday cup electrostatic charge measurements were attempte d. Approximately 15 % of the successfully synthesized poly( 2 HEMA ) droplets were able to be measured for charge as the rest did n ot display electret qualities.

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73 The cha rge on the measured polymer sphere electrets had very high variance Only a select few retained the electre t behavior and could be observed to electrostatically stick to a metal spatula Figure 2. 8 While the majority had low charge measurements in the nC range that were less than 10% of total charge observed on the 2 HEMA droplets of equal volume, t he rem a in in g few that did exhibit electrostatic attractiveness had maintained similar charge measurements as their liquid pre polymerized counterparts. Time was the final item detriment al to the poly(2 HEMA) electret as all lost electrostatic capabilities after 3 days. This may be attributed to the high loading of initiator creating lower molar mass poly(2 HEMA). High initiator content could have significantly lowered the glass transition temperature from a normal high molar mass poly(2 HEMA) sample approximatel y around 90 to 100 C allowing relaxation within the polymer. Additionally, local humidity could have been absorbed by the hydrophilic poly(2 HEMA). The added water conten t would also allow for relaxations to occur in the polymer permit t ing charge migrat ion. Figure 2. 8. 180 nL p oly(2 HEMA) with 2.0wt% Benacure TM exhibiting electrostatic a ttraction toward metal spatula.

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74 2.4 Conclusion Our experiments have shown that a nL IBF device (syringe) can launch a drop to a target where its charge it can be measured even at high potential in real time. As the double layer and hence the ability to determine the deposition of nL solution volumes in real time. This proof of concept effort shows that IBF charge measurements can be used to monitor MALDI depositions for QC purposes potentially correct MALDI data for volume deposition differences, doing so in real time. One might extend this idea to robotically based MALDI p late preparations, tissue MALDI experiments or LC/MALDI. With feedback one could dynamically correct deposition volumes in real time to improve dispensing accuracy. Finally, as IBF can be applied to dispense viscous liqui ds, from monomers as shown here a nd elsewhere [1, 4 7, 29] to samples including human serum; heparin i zed whole human blood or other body fluids, our approach could afford a valuable QC mechanism for MALDI assays of these important liquids. Verifying the dispensing event and its volume in real time could allow molar correction or alignment via charge measurements and might realize the goal of a routinely quant itative MALDI. With respect to electret formation it is believed that the choice of polymer poly(2 HEMA) did not allow for sufficient locking in of surface doub le layer charge. This may be in part due to the fact that the glass transition temperature of poly(2 HEMA) was sufficiently low to allow for molecular rearrangement due to the high amount of initiator. This relaxation may have allowed for the charges to migrate. In the chapter addressing future work plausible solutions for successful polymer el ectret synthesis are forwarded.

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75 2.5 References 1. Sauter AD. Precise Electrokinetic Delivery of Minute Volumes of Liquid(s). United States Patent 6,149,815. Nov. 21, 2000. 2. Sauter Jr AD. N Channel, Y Energy Mode, Z Coupled Nested Gaussian Surfaces for Liquid(s) Dispensing, Liquid(s) Treatment, Liquid(s) Introduction and Solid(s) Production Methods and Apparatus. United States Patent 7,749,447 B1. Jul. 6, 2010. 3. Delgado AV, Gonzlez Caballero F, Hunter RJ, Koopal LK, and Lyklema J Journal of Colloid and Interface Science 2007;309(2):194 224. 4. Sauter Jr AD American Laboratory 2007;39(3):22 29. 5. Tu T, Sauter Jr AD, Sauter 3rd AD, and Gross ML Journal of the American Society for Mass Spectrometry 2008;19(8):1086 1090. 6. Hilker B, Clifford KJ, Sauter AD, Gauthier T, and Harmon JP Polymer 2009;50(4):1015 1024. 7. Yergey AL. National Institutes of Health, Personal Communication. Bethesda, MD 2008. 8. Colquhoun DR, Schwab KJ, Cole RN, and Halden RU Applied and Environment al Microbiology 2006;72(4):2749 2755. 9. Fernndez F, Cody R, Green M, Hampton C, McGready R, Sengaloundeth S, White N, and Newton P ChemMedChem 2006;1(7):702 705. 10. Ding C. Qualitative and quantitative DNA and RNA analysis by matrix assisted laser de sorption/ionization time of flight mass spectrometry. In: Lo YMD, Chiu RWK, and Chan KCA, editors. Methods in Molecular Biology: Humana Press Inc, 2006. pp. 59 71. 11. Rozylo JK, Berezkin VG, Malinowska I, and Jamrozek Manko A Jpc Journal of Planar Chrom atography Modern Tlc 2001;14(4):272 276. 12. Sessler GM Journal of Electrostatics 2001;51 52:137 145. 13. McCarty LS, Winkleman A, and Whitesides GM Journal of the American Chemical Society 2007;129(13):4075 4088. 14. Qiu X J. Appl. Phys. 2010;108:011101/011101 011101/011119. 15. Datta S and Conlisk AT. Role of Multivalent Ions and Electrical Double Layer Overlap in Electroosmotic Nanoflows. In Proceedings of the 47th AIAA Aerospace Sciences Meeting. Orlando, FL, 2009.

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76 16. Hitzer E Memoirs of the Faculty of Engineering, University of Fukui 2001;49(1):45 53. 17. Kebarle P and Tang L Analytical Chemistry 1993;65(22):972A 986A. 18. Song SP and Li BQ International Journal of Computational Fluid Dynamics 2001;15(4):293 308. 19. Millikan RA Physical Review 1913;2(2):109. 20. Amster IJ Journal of Mass Spectrometry 1996;31(12):1325 1337. 21. Sauter AD Journal of the Association for Laboratory Auto mation 2002;7(2):52 55. 22. Halliday D and Resnick R. Physics New York: Wiley 1962. 23. Ferrante J and Smith JR Physical Review B 1985;31(6):3427. 24. Low level Measurements Handbook, 6th ed. ed. Cleveland, OH: Keithly Instruments, Inc. 25. Thomson B A and Iribarne JV Journal of Chemical Physics 1979;71(11):4451 4463. 26. Keithley Instruments. Low level measurements handbook : Precision DC current, voltage, and resistance measurements, 6th ed. Cleveland, OH: Keithley, 2008. 27. Han KN. Fundamentals of Aqueous Metallurgy. Littleton, CO: Society for Mining, Meallurgy, and Exploration, Inc., 2002. 28. Sauter Jr AD. Nanoliter, LLC. Personal Communication. Henderson, NV USA, 2008. 29. Hilker B, Clifford KJ, Sauter AD, and Harmon JP Journal of the Ameri can Society for Mass Spectrometry 2009;20(6):1064 1067.

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77 CHAPTER 3 : DIELECTRIC ANALYSIS OF POLY(METHYL METHACRYLATE) ZINC(II) MONO PINACOLBORANE DIPHENYLPORPHYRIN COMPOSITES 3.1 Introduction The purpose of this investigation is to understand the structure property relations of metalloporphyrin containing polymer s because metalloporphyrins are of current interest in sensors, sequestration, and de struction of target analytes. Recent porphyrins [1 10] This has led to an impressive novel library of functionalized porphyrins with the ability to provide additional custom porphyrins and corrol es for specific applications. Currently, there is a lack of information about the interactions and structure property relations of porphyrins in polymer systems. Dielectric spectroscopy provides information about the segmental mobilit y of a polymer [11] Polymers that have repeating units whose dipole vector summation accumulates can be studied via Dielectric Analysis (DEA). Different conf ormational states of the polymer can be studied via this method. When DEA is performed upon polymer composites, interactions between the filler and pol ymer can be better understood. To obtain quality DEA spectroscopy the polymer and filler materials mus t possess a permanent or inducible dipole [12]

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78 Typically, DEA is performed by subjecting a sample to an alternating electric field while placed betwe en a parallel plate capacitor. The sample will then be subjected to a discrete temperature range and frequency sweep. The dielectric constant (permittivity temperature, and frequency. These measurements allow for the examin ation of specific segmental relaxations by analysis of the different maxima observed. The molecular relaxations by convention start their assignment sequentially, from high to low temperature, with alpha ( ), then beta ( ), gamma ( ), and so forth. The relaxation is associated with the glass transition (Tg) of the polymer and is attributed to the main chain translation (backbone) [11] The relaxation can ma nifest in five possible scenarios that are well described by Garwe et al [13] From these five scenarios the relaxation can be dete rmined using Arrhenius plots (natural log (ln) frequency versus inverse temperature). Arrhenius plots may be linear or nonlinear. Nonlinear plots can be curve fitted using the Vogel Fulcher Tamman (VFT) or W illiams Landel Ferry (WLF) laws [14, 15] The relaxation Arrhenius plots o btained from DEA also can be linear revealing apparent activation energy (E a ) [16 20] Whether the Arrhenius plot is linear or nonlinear depends upon several factors that occur when the cooperative relaxations m anifest their split. For more detailed information explore reference [13] by Garwe and associates. occur below the Tg and are specific to the moieties of each polymer tested representing rotational reorientation fr om the applied electric field. These sub Tg (lower temperature) relaxations characteristically exhibit linear behavior in Arrhenius DEA plots [11, 21]

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79 Individual relaxations can become more complex when constructive or destructive cooperation manifests. The merging of different mole cular relaxations commonly occurs, for example an merge [17 20, 22 26] This results when the two separate molecular relaxations have sufficient overlap in the DEA spectrum and their reorientation to the applied electric field i s in resonance or cooperative. Conductivity relaxations occ ur at temperatures significantly abo ve the Tg. Aptly, the temperature region in which this occurs is called the conductivity region. This region is significant because the polymer exhibits minimal viscoelastic effects allowing the researcher to obtain al ternating current (AC) and direct current (DC) conductivities as well as their respective activation energies for ion translation [21, 22, 27, 28] Conductivity relaxation spectra were fit u sing the Havriliak Negami (H N) [29] This allows for unbiased analysis [30] Use of the H N fit upon the conductivity relaxation region reveals structure property relationships in the absence of predominating viscoeleastic effects that occur below the Tg revealing an idealized te mperature region to study the ionic transpo rt across the polymer matrix. In this study, tan delta (tan the ratio of the imaginary to the real dielectric was employed to measure the dissipation factor of PMMA and PMMA Zn(II)Bpin DPP c omposites. This measurement is insightful because it reveals how the polymer matrix dissipates the applied electric field as heat or in some cases conductive transport [31] The dissipation factor is an important characteristic of the composite as it can identify how certain materials will behave in various electronic environments. For example, the dissipation factor c an lend insight into whether the composite would be

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80 suited for use as a dielectric in a capacitor, or if the composite could function as a non attenuating casing for an electronic device. Fluorescence spectroscopy can yield the optical properties of the e mbedded porphyrin and can also provide key information regarding the solvation and/or aggregation state of the macrocycle. Highly ordered porphyrin aggregates typically exhibit large hypsochromic or bathochromic shifts of the optical absorption bands, sig fluorescence lifetimes depending on the type of aggregates [32 35] The higher energy face to face H aggregates display hypsochromically shifted absorption spectra and significant emission quenching with respect to the monomer while the lower energy side by side J aggregates result in bathochromically shifted absorption spectra, in addition to a large stokes shift and increased quantum yie ld [32 34] Poly( methyl methacrylate) (PMMA) has been widely studied via DEA and offers a great starting point for the first full investigation of porphyrin PMMA composite molecular interactions [13, 16, 18 20, 22, 24, 25, 30 36 39] PMMA generally has two dielectrically active relaxations, and and a conductivity relaxation. The relaxation is attributed to the main chain (backbone) translation slippage [11] relaxation corresponds to the motion of the [(C=O)OCH 3 ] side gr oups attached to the main chain [32] Note t hat for pure PMMA, the relaxati on, ( CH 3 ), has not yet been observed using DEA. The relaxation is not typically observed with DEA because the ( CH 3 ) moiety is not significantly polarizable [36, 38] However, it is possible to observe the relaxation of PMMA composites when the local environment permits such cooperation whereas to make the ( CH 3 ) sufficiently

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81 polarizable Our group has observed the electrically active relaxation of PMMA carbon nanotube composites [24] Porphyrins have been of great interest to chemists and engineers in recent times because they have been shown to be very useful in various ar eas such as dye sensitized solar cells (DSSCs), catalysis, polymer light emitting diode s (PLEDs), and light harvesting [40 44] Recently, porphyrins have become the interest of this group because of their potential ability to sequester nerve agents, choking agents, and biological agents for la ter photocatalytic destruction. In this study, dielectric analysis enabled the exploration into the interaction of a metalloporphyrin, [5 (4',4',5',5' tetramethyl[1',3',2']dioxaborolan 2' yl) 10,20 diphenylporphyrinato]zinc(II), ( Zn(II)Bpin DPP), with PMMA. I n the literature there is a deficiency of DEA information with respect to the interactions of porph yrins with polymeric systems. Furthermore, DEA performed upon PMMA generally stops at temperatures (<190 C) before the first of a two part degradation proc ess which begins at ca. 220 C. To our knowledge, this is the first study to both probe the complete dielectric interactions of a porphyrin polymer composite system as a function of time, temperature, and frequency while testing thermally beyond the first of a two part degradation process. by making use of the H [45] This analysis shows supportive evidence for the first of a two part degradation process of PMMA that manifests as en d chain scission of viny l idine units regenerating methyl methacrylate (MMA) [46 48] This is the first study to analyze PMMA degradation using DEA through the components of both the complex permittivity and complex electric modulus M*

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82 3. 2 Experimental 3.2.1 Experimental Reagents The methyl methacrylate (MMA) monomer was purchased from Aldrich azobis(2,4 dimethylpentane nitrile) (VAZO 52) initiator was purchased from DuPont (Wilmington, DE). The solvents used, including reagent grade dichloromethane (CH 2 Cl 2 ) and reagent grade methanol (MeOH), were purchased from Fisher Scientific (Pittsburgh, PA). The monomethyl ether hydroquinone (MEHQ) inhibitor was removed from the MMA using a fresh MEHQ inhibitor remover column available from Aldrich (Milwaukee, WI). All other materials were used without further purification. Fresh 30g columns were pack ed with Aldrich HQ/MEHQ Inhibitor remover (CAS 9003 70 7). These 30g columns can remove 100ppm HQ/MEHQ from 3L of MMA monomer, which contains 10 100ppm HQ/MEHQ inhibitor. 50mL of monomer were purified ensuring all inhibitor was removed. 3.2.2 Synthesis o f Zinc monoborate diphenyl porphyrin (Zn(II)Bpin DPP) [5 (4',4',5',5' tetramethyl[1',3',2']dioxaborolan 2' yl) 10,20 diphenyl porphyrinato]zinc(II) (zinc monoborate diphenylporphyrin) (Zn(II)Bpin DPP) was synthesized by following the synthesis set forth by Hyslop et al. Figure 3. 1 1 H NMR and UV vis spectra were obtained to confirm the synthesis of the Zn(II)Bpin DPP molecule [49] 1 H NMR (400 MHz, CDCl 3 H), 9.94 (d, J = 4.8 Hz, 2H, Ph), 8.22 ( d, J = 2.0 Hz, 2H, H Ph), 7.78 (m, 6H, H Ph), 1.85 (s, 12H, 0 C(CH 3 ) 2 C(CH 3 ) 2 O )

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83 UV vis Zn(II) BPin DPP (CH 2 Cl 2 (3.60), 540 (4.29), 573 (3.57) nm. Figure 3. 1 Synthesis of Zn(II) Bpin DPP followed by zinc metallization. 3.2.3 Poly(methyl methacrylate) synthesis Poly(methyl methacrylate) (PMMA) was synthesized via radical chain azobis[2,4 dimethylvaleronitrile], was added to and disso lved in deinhibited methyl methacrylate monomer Figure 3. 2 The s olution was polymerized in bulk at 60 C for 18 hours under an inert atmosphere of N 2 gas inside a scintillation vial. The low polymerization temperature ensured an even polymerization and bubble free samples were obtained. High molar mass polymer was verified using DS C showing high Tg The resulting polymer was then dissolved in CH 2 Cl 2 and then precipitated in methanol to remove any impurities and dried under vacuum at 110 C for 48 hours

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84 Figure 3. 2 Synthesis of poly(methyl methacrylate). 3.2.4 PMMA Zn(II)Bpin DPP composite synthesis Four formulations were made for DEA experimentation. A control, PMMA, and 3 different weight percents (wt%s) (w/w) (0.05, 0.11, 0.9) were made by dissolving the polymer and dye in CH 2 Cl 2 Figure 3. 3 (a), then removing the solvent via a vacuum oven at 80 C for 48 hours. S cintillation vials were broken to remove the samples. Samples were then molded in a Carver press as described in section 3.2.5.4 Furthermore, four additional samples were made for fluorescence spectroscopy following the same procedure to ascertain aggreg ation and fluorescence lifetimes. A control, PMMA, and 3 different wt% composites (0.1, 0.3, and 1.31 wt%) were prepared Figure 3. 3 PMMA and PMMA Zn(II)Bpin DPP composite samples. (a) poly(methyl methacrylate) control, 0.05, 0.11, 0.9 wt% Zn(II)Bpin DPP samples prepared for solution casting. (b) Carver thermal pressed samples (control & 0.11 wt% composite). a b methyl methacrylate MMA Vazo 52 poly(methyl methacrylate) PMMA

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85 3.2.5 Instrumentation 3.2.5.1 H 1 NMR A Varian Inova 400 MHz NMR spectrometer was used to obtain 1 H NMR spectra of the porphyrin molecule. 3.2.5.2 UV/VIS Spectroscopy A Perkin Elmer Lambda 40 spectrophotometer was used to obtain spectra on four separate molar concentrations of Zn(II)Bpin DPP in CH 2 Cl 2 The four samples were made to ensure that the gr eatest maximum absorbance of the Soret band was below and sec ondary bands were calculated. 3.2.5.3 Fluorescence Spectrometer For absorption and emission spectra the samples were mounted onto a glass slide using a minimal amount of vacuum grease. Visible absorption spectra were collected on a home built instrument. White light from a 60W tungsten bulb was fed into a fiber optic cable and th r ough the sample. The tra nsmitted light was then collected using a second fiber optic cable and fed into a USB 2000 Ocean Optics CCD camera. Ocean optics software was used to acquire and process the optical absorption data. Steady state fluorescence measurements were carried out using an ISS PC1 spectrofluorimeter. The samples were placed in the PC1 sample holder at a 57 o angle relative to the excitation source. The samples were excited at 414 nm and the emission monochrometer scanned from 550 to 750 nm. Time resolved fluoresc ence decays were obtained by placing the samp les as described above into a 1 cm sample holder in the optical path of our home built fluorescence lifetime instrument. The samples were

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86 oriented 57 o to the excitation pulse. The excitation pulse was derived from a Continuum Leopard II frequency doubled Nd:YAG laser (< 20 ps pulse width, 532 nm, 20 Hz, ~ 30 mJ/pulse). The emitted light was passed through a focusing lens, and onto the face of an Electro Optics Inc., EOT 2030 amplified Si Diode (300 ps rise/fal l time). The resulting signal was digitized using a Tecktronix TDS7404 4 GHz DPO. Traces are the average of ~20 laser pulses. 3.2.5.4 Sample molding Samples were compression molded using a Carver Press (Wisconsin, USA) equipped with a heating element at a temperature of 160 C at a pressure of 13,788 KPa (2000 psi) to the dimensions of 25 mm x 21.5 mm x 0.6 mm. Samples were held at these conditions fo r 10 minutes and then cooled to room temperature. Samples were then stored under vacuum at 50 C until ready for DEA analysis, Figure 3. 3 ( b ). 3.2.5.5 Differential Scanning Calorimetry DSC A TA Instruments 2920 DSC instrument was used to calculate the glas s transition temperature (Tg) of the PMMA control and PMMA composites. PMMA and composite samples mass ranged from 5 10 mg and were placed in an open aluminum pan. An inert environment was created in the cell using N 2 at a flow rate of 60 70 mL/min. Sa mples were first equilibrated at 30 C and held isothermal for 2 minutes then scanned at a rate of 7 C/min up to 150 C. All samples were air cooled in the same manner by removing the heat source and equilibrating at ambient temperature for 15 minutes at 20 C. Sample data was taken on the second run in order to remove any thermal history following the same procedure.

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87 3.2.5.6 Dielectric analysis DEA Dielectric analysis was performed using a TA Instruments DEA 2970. The sample was heated to 150 C and then taken down to the cryogenic temperature of 150 C. A TA single surface sensor was employed where a maximum force of 250 N was applied to achieve the minimum spacing of 0.30 mm. Measurements were taken in 5 C increments from 150 to 270 C. Frequencies tested ranged from 0.3 Hz to 1 00 k Hz. The measurements were taken under an inert argon atmospheric purge of 600 mL/min. Capacitance and conductance were measured as a function of time, temperature, and frequency to obtain the dielectric consta 3.2.6 Data Fitting Non linear regression H N analysis was performed using Oakdale Engineering DataFit 9.0 (Oakdale, PA USA). 3.3 Results 3.3.1 Dipole Moment Zn(II)Bpin DPP Because DEA works by detec ting permanent or inducible dipoles, a computational calculation of the electronics of Zn(II)Bpin D PP was performed and presented. Calculation of the dipole was performed using Gaussian03 [50] on an SGI Altix through the Teragrid [51] and using Gamess [52] Research Computing. All ca lculations were performed using density functional theory (DFT). Results obtained from DFT can depend on the choice of functional. As such, care was taken in selecting functionals and basis sets appropriate for the calculations performed. Additionally, comparisons were made between several choices of basis sets

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88 and density functional. The structure was first optimized using the B3LYP density functional and a 6 31G* basis set. The dipole moment of the optimized structure, computed at the same level of t heory, was found to be 2.63 Debye. A density functional that has been developed specifically for calculations involving transition metals, the M06 L functional, a local functional, was also employed for comparison [53] The structure was reoptimized using the M06 L density functional with the LANL2TZ basis set on the zinc center and 6 31G* on the rest of the atoms. The M06 L functional resulted in a dipole of 2.87 Debye. A final comparison is made to the dipole calculated using the M06 functional, recommended for use in calculations involving organometallic systems [53, 54] Using the M06 functional in conjunction with the LANL2TZ/6 31G* mixed basis set detailed above resulted in a dipole of 2.77 Debye for the optimized geometry. All three computed dipoles are in good qualitative agreement. In all cases, the dipole points along a vector drawn from the zinc center of t he porphyrin to the boron containing substituent. This is the conventional definition of the dipole moment in which the vector is taken to point from negative to positive charge density. In Figure 3. 4 ( a ) Zn(II)Bpin DPP structure is provided along with th e optimized structure in Figure 3 4 ( b ) As a point of reference, Table 3. 1 lists Zn(II)Bpin DPP along with a few common solvents with their perma nent dipoles values in Debyes (D) (1 D = 10 18 statcouloumb cm 30 Cm).

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89 Table 3.1. Dipole moment of Zn(II)Bpin DPP compared with common solvents. Solvent Dipole moment (D ) Methanol 1.7 Water 1.85 Zn(II)Bpin DPP 2.87 Acetone 2.88 Acetonitrile 3.92 Figure 3. 4 Zn(II)Bpin DPP. (a) Line structure Zn(II) Bpin DPP (b) Optimized Zn(II)Bpin DPP as computed at the B3LYP/6 31G* level of theory. with inset ( x y z ) orientation guide. 3.3.2 UV vis Spectroscopy UV vis spectra obtained, Figure 3 5 shows a Soret band at 410.5 nm which contains a left shoulder at 391 nm. A secondary peak is observed at 540 nm flanked on each side by shoulders at 506 and 572.5 nm (expanded right side y axis) The UV vis spectrum confirms the presence of the met alloporphyrin revealing one So ret b and and a single secondary peak [55] In contrast, free base porphyrins that do not contain metal ions characteristica lly contain one Soret band with 4 Q bands occurring at higher wavelengths [55] Axis a b

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90 Figur e 3 5 UV vis spectrum of 1.964x10 6 M solution Zn(II)Bpin DPP in CH 2 Cl 2 The right secondary Y axis corresponds to the expanded view of the absorbance peak upon 540 nm. 3. 3.3 Fluorescence Spectroscopy The optical properties of three PMMA slides doped with a range of concentrations of Zn(II)Bpin DPP where examined to determine the degree of porphyrin aggreg ation. Figure 3 6 displays the absorption spectra for the various samples examined. Only the visi ble region (450 nm to 650 nm) is displayed as the absorbance in the Soret region (<450 nm) was too large to be of use in the analysis of aggregation. The spectra displayed in Figure 3 .6 exhibit absorption bands centered at 506 nm, 546 nm, and 580 nm for e ach of the composites and are nearly identical to those of the porphyrin in solution.

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91 Figure 3. 6 Normalized absorption spectra in the visible region for the polymer samples as well as free Zn(II)Bpin DPP in ethanol. Figure 3 7 Normalized emission spectra for all of the polymer samples as well as Zn(II)Bpin DPP exc = 414 nm).

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92 The corresponding steady state emission spectra are displayed in Figure 3 7 In all cases, the emission spectra display two emission peaks centered at ~592 nm and ~640 nm (414 nm excitation). The 640 nm emission band is ~4 nm hypsochromically shifted relative to Zn(II)Bpin DPP in solution. The subsequent emission lifetimes for both the low and high loading composites are slightly longer th an that observed for the porphyrin in solution consistent with the porphyrin being in a more hydrophobic environment [ 35] However, the higher loading composite displays an emission lifetime significantly shorter than the corresponding lower loading composite suggesting some degree of porphyrin porphyrin interaction. The optical absorption and emission data are summa rized in Table 3. 2 Table 3.2 Summary of fluorescence decay lifetimes for composite samples (0.3 and 1.3 wt%), metaloporphyrin Zn(II)BpinDPP, and the free base porphyrin H 2 BpinDPP. Sample 1 (ns) 1.3 wt % 2.56 0.3 wt % 3.09 Zn(II)Bpin DPP/MeOH 2.31 H 2 Bpin DPP 8.97 The observed 1 nm bathochromic shift of the absorption band centered at 546 nm excludes the possibility of H aggregates. J aggregates characteristically display a shift. Since the PMMA slides exhibit a slight loading indicates little or no porphyrin aggregation within the polymer matrix. In addition, the fluorescence emission dec ays fit to a monophasic exponential, indicating a homogeneous population of emitters consistent with a significant monomer population.

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93 3.3 .4 DSC DSC data was obtained for the PMMA control and PMMA Zn(II)Bpin DPP composite samples. The glass transition temperature (Tg) was shown to increase slightly with increasing wt% (w/w). The Tg temperatures for samples tested are listed in Table 3. 3 The observed increase in Tg reveals that Zn(II)Bpin DPP may b e acting as an antiplasticizer. Figure 3. 8 shows DSC stacked (Y axis) spectra of PMMA and PMMA Zn(II)Bpin DPP composites (0.05, 0.11, 0.9 wt%). Table 3.3. DSC glass transition (Tg) temperatures ( C) for PMMA and PMMA Zn(II)Bpin DPP composites at respective wt%s. Sample Tg ( C) PMMA 105.2 0.05 wt% 119 0.11 wt% 119.9 0.9 wt% 123 Figure 3. 8 DSC y axis stacked spectra of PMMA & PMMA Zn(II)BpinDPP (0.05, 0.11, 0.9 wt%) composites. Zn(II)Bpin DPP anti plasticized PMMA

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94 3. 3.5 Dielectric analysis (DEA) In DEA, the material is exposed to an alternating electric field generated by an applied sinusoidal voltage. The applied electric field causes the alignment or induction of dipoles in the material which results in polarization. Since both the polymer (PMMA) and the dye (Zn(II)Bpin DPP) posse ss a permanent dipole moment, DEA can measure two fundamental characteristics of the composite: capacitance and conductance as f ( t ,T,f) [12] The capacitive nature of the material is its ability to store electrical charge electric charge. One feature of DEA is that this spectroscopy allows for the investigation of molecular mobility, or relaxations of the material. The complex permit Eq. 3. 1 of a system is defined [21] : (Eq. 3. 1) (Eq. 3. 2) (Eq. 3. 3) Eq. 3. 2, is the real part of the complex relative permittivity (dielectric constant) and represents the amount of dipole alignment both induced and permanent. Eq. 3. 3, is the dielectric loss (loss factor) and represents the dipole loss factor plus ionic condu ction. The classic Debye equation E q. 3. 4 was introduced to account for dielectric effects on dilute polar solutions [56, 57] McCrum et al [21] se parated the real and imaginary components of the classic Debye 3. 5 and Eq 3. 6 which were later modified to account for ionic conductivity Eq. 3.7 as follows [12] :

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95 ( Eq. 3. 4 ) ( Eq. 3. 5 ) ( Eq. 3. 6 ) ( Eq. 3 .7 ) S ) S : static dielectric permittivity at zero frequency : dielectric permittivity at high frequency 0 : absolute permittivity of free space (8.854 X 10 14 F/cm) 3. 3.5.1 Permittivity The permittivity of a dielectric material is measured relative to that of a vacuum 0 = 8.85 x 10 12 Fm 1 ) [58] induced and permanent within the sample. Permittivity was observed to increase with increasing temperatur e a nd decreasing frequency, Figure 3. 9 (a d)

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96 Figure 3.9(a) Figure 3. 9 ( b )

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97 Figure 3.9(c) Figure 3. 9( d) Figure 3. 9. Permittivity versus temperature ( C). (a) PMMA, (b) PMMA Zn(II)Bpin DPP 0.05wt%, (c) PMMA Zn(II)Bpin DPP 0.11wt%, and (d) PMMA Zn(II)Bpin DPP 0.9wt%. Figures 3. 10 ( a ) and ( b ) show permittivity for 70 C and 25 C, respectively. The permittivity increases to maximum amount when 0.11 wt% of Zn(II)Bpin DPP was added. permittivity when loading was beyond 0.11 wt% at standard temperature and pressure (STP) At 25 C, a decrease in permittivity could be observed at frequencies above ca. 600 Hz for the 0.9

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98 wt% sample. In comparison, at 70 C the 0.11 wt% and 0.9 wt% samp les achieved the m aximum observed permittivity. From these observations, it appears the PMMA Zn(II)Bpin DPP composites reach a maximum permittivity loading capacity ca. 0.11 wt% of Zn(II)Bpin DPP for STP conditions. The noted decrease in permittivity tha t appears at 25 C (above 600 Hz), but disappears at 70 C is explainable by considering the added thermal energy within the system. As the thermal energy rises there is an increase in the free volume of the composite allowing for the greater reorientati on of dipoles in the composite in response t o the applied electric field. Since only the higher frequencies tested (600 Hz 100 k Hz) showed the decrease, it is possible that the composite was above the maximum loading capacity with resp ect to permittivity increase. Therefore, this sample had the porphyrin packed tightly not affording the proper free volume nor the time to allow for reorientation to the applied electric field. Figure 3.10(a).

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99 Figure 3. 10 (b) Figure 3. 10 Permittivit frequency (Hz). (a) 70 C and (b) 25 C. 3.3.5.2 Electric Modulus McCrum et al. showed that by inverting the complex permittivity one could obtain the complex electric modulus Eq. 3. 8 [21] Ambrus, Moynihan, and Macedo were the first to publish the electric modulus for the investigation of electrical relaxation phenomena in vitreous ionic conductors [27] ( Eq. 3. 8 ) M : complex electric modulus electric storage modulus electric loss modulus The electric modulus formalism is particularly useful when applied to dielectric spectra of polymers and polymer composites. Polymers and polymer composite systems contain interfacial polarization, also known as the Maxwell Wagner Sillars (MWS) effect [59 61] The MWS effect is present because fillers, additives, a nd even

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100 impurities can c reate a heterogeneous system. In systems that contain conductive components interfacial relaxation can be obscured by the conductivity, essentially masking targeted molecular relaxations. Employment of the electric modulus reveals the relaxations obscured by ionic conductivity by subtracting the conductivity effects and revealing the molecular relaxations. 3.3.5.3 max become visually distinguished. type character as reported by Garwe et al. [13] Garwe et al prepares behavior and manifests as a nonlinear curves as seen in Figures 3. 11 (a d) and is remains which exhibits linear characteristics. Figure 3.11(a)

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101 Figure 3.11(b). Figure 3.11(c).

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102 Figure 3.11(d). Figure 3. 11 max ) v ersus 1/T (K (a) PMMA, (b) PMMA Zn(II)Bpin DPP 0.05 wt%, (c) PMMA Zn(II)Bpin DPP 0.11 wt%, and (d) PMMA Zn(II)Bin DPP 0.9 wt%. These Arrhenius diagrams can also be plotted using the electric modulus max ), Figures 3. 12 ( a d ). seen in these trace plots th at at higher frequencies of 30 kHz to 100 k Hz a nonlinear entailed. Even with performing such an analysis the nonli max ) versus inverse temperature. Furthermore, the employment of the electric modulus formalism is known to make significant changes in plots that differ from those cr eated with the loss f [22, 23] Differences visoc elastic and conductivity relaxations. Although these differences exist, the electric

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103 modulus formalism as shown here reproduces the same data when analyzed and is invaluable to the exploration into the conductivity relaxations in polymer composites [22, 23] Figure 3.12(a) Figure 3 12 ( b )

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104 Figure 3.12(c). Figure 3 12 ( d ) Fig ure 3. 12 max ) v ersus 1/T (K (a) PMMA, (b) PMMA Zn(II)Bpin DPP 0.05wt%, (c) PMMA Zn(II)Bpin DPP 0.11wt%, and (d) PMMA Zn(II)Bpin DPP 0.9wt%.

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105 3.3.5.4 The beta ( versus temperature, Figures 3 1 3 (a d) Figures 3 1 4 (a d). T he conductivity relaxat ions are obscured by MWS effect and Figures 3 1 4 ( a d ) a nd are discussed later. Notice the clarity of the relaxation plots in 3 1 3 (a d) This relaxation is attributed to the motion of the [(C=O)OCH 3 ] side groups attached to the main chain [38] PMMA is unique in that it has a large temperature range in which this relaxation occurs when c ompared to othe r polymers. This relaxation obeyed Arrhenius behavior which is characteristic of secondary relaxations in polymers. Arrhenius plots of ln frequency versus the reciprocal of temperature were created where the slope was used to generate the apparent activa tion energy, E a ut ilizing the following equation Eq. 3 9 [11, 21] ( Eq. 3. 9 ) E a : :Activation Energy R: :Ideal gas constant f o : Pre exponential factor (conductivity at infinite temperature) T : Temperature (K)

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106 Figure 3.13(a). Figure 3. 1 3 (b)

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107 Figure 3.13(c). Figure 3. 1 3 (d) Figure 3 1 3 L oss factor C) plots 0.3 Hz to 100 kHz. (a) PMMA. (b) PMMA Zn Bpin DPP 0.05 wt% (c) PMMA Zn Bpin DPP 0.11 wt%. (d) PMMA Zn Bpin DPP 0.9 wt% (w/w)

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108 Figure 3.14(a). Figure 3. 1 4 (b)

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109 Figure 3.14(c). Figure 3. 1 4 (d) F igure 3. 1 4 E C) plots 0.3 Hz to 100 kHz. (a) PMMA. (b) PMMA Zn Bpin DPP 0.05 wt%. (c) PMMA Zn Bpin DPP 0.11 wt%. (d) PMMA Zn Bpin DPP 0.9 wt% (w/w). The apparent activations energies were calculated two ways for compari son. activation energy, E a was evaluated with Arrhenius plots of ln f max max ) ) versus inverse temperature. The second method was similar, but involved the use of th e

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110 temperature plots. The second method obtained the apparent E a using Arrhenius plots of ln f max max ) ) versus inverse temperature. It is the intent to compare the two m ethods and highlight their similarities and differences. 3. 3. 5. 4.1 max ) elaxation maxima occurred 0.3 to 1000 Hz (2 to 85 o C) for PMMA; 0.3 to 300 Hz (0.8 to 65 o C) for PM MA Zn(II)Bpin DPP 0.05wt%; 0.3 to 300 Hz (4.8 to 65 o C) for PMMA Zn(II)Bpin DPP 0. 11wt%; and 0.3 to 300 Hz ( 3.4 to 61 o C) for PMMA Zn(II)Bpin DPP 0.9 wt%. Table 3 4 lists max peak temperature at 300 n shared amongst all samples. This shows max ) peak at 300 Hz to decrease with increasing porphyrin content. The additional loading of Zn(II)Bpin DPP trends the observed maxima to lower temperatures 3000 Hz to 300 Hz. The apparent E a are listed in Table 3. 5 The apparent E a obtained for PMMA 78.22 kJmol 1 (18.69 kcalmol 1 ), PMMA Zn(II)Bpin DPP 0.05wt% 81.1 kJmol 1 (19.4 kcalmol 1 ), PMMA Zn(II)Bpin DPP 0.11wt% 81.47 kJmol 1 (19.47 kcalmol 1 ), and PMMA Zn(II)Bpin DPP 0.9wt% 77.6 kJmol 1 (18.5 kcalmol 1 ) allows for the conclusion that the apparent E a the porphyrin at these wt%s. Table 3.4. Comparison of max ) & max ) peak maximums at 300 Hz for PMMA and PMMA Zn(II)Bpin DPP composites. max ) ( C) max ) ( C) PMMA 69 56.67 0.05 wt% 65 52 0.11 wt% 65 52 0.9 wt% 61 49.3 The two methods show that increasing porphyrin content trends maxima to lower temperatures ( o C)

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111 Table 3.5. Comparison of apparent E a PMMA Zn(II)Bpin DPP composites. M'' E a 1 ) E a 1 ) E a 1 ) E a 1 ) PMMA 78.2 18.7 79.3 18.9 0.05 wt% 81.1 19.4 78.9 18.8 0.11 wt% 81.4 19.4 82.8 19.8 0.9 wt% 77.6 18.5 80.3 19.2 3. 3.5.4.2 max ) The employment of the electric modulus formalism showed the well documented shift of peak maxima to lower [22, 23] versus temperature plots re vealed to 1000 Hz ( 7.4 to 70.4 o C) for PMMA; 0.3 to 300 Hz ( 10 to 52.0 o C) fo r PMMA Zn(II)Bpin DPP 0.05wt%; 0.3 to 300 Hz ( 5.9 to 52.0 o C) fo r PMMA Zn(II)Bpin DPP 0.11wt%; and 0.3 to 300 Hz ( 10.9 to 49.3 0 C) for PMMA Zn(II)Bpin DPP 0.9wt% Table 3 4 max ), the same trend of max ) with increasing porphyrin content as was calculated max ). The difference is the shift of these maxima to lower temperatures using The apparent E a 3. 5. The apparent E a obtained for PMMA 79.31 kJmol 1 (18.95 kcalmol 1 ), PMMA Zn(II)Bpin DPP 0.05wt% 78.93 kJmol 1 (19.4 kcalmol 1 ), PMMA Zn(II)Bpin DPP 0.11wt% 81.47 kJmol 1 (19.47 kcalmol 1 ), and PMMA Zn(II)Bpin DPP 0.9wt% 77.6 kJmol 1 (18.5 kcalmol 1 ). Although the shift of the maxima occur at lower temperatures the apparent E a

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112 The apparent E a addition of the porphyrin dye a ppeared to have no appreciable effect upon the apparent apparent E a Therefore, the addition of the Zn(II)Bpin DPP had no influence upon the rotation of the [(C=O)OCH 3 ] group. Thus alternatively arriving at the conclusion showing the apparent E a for th loading at the tested wt%s. Furthermore, literature values for the relaxation for PMMA generally range b etween 71 to 84 kJmol 1 (17 to 20 kcalmol 1 ) [17, 19 21, 24, 25, 36, 38] The valu es obtained in this study 78 .2 to 79.3 kJmol 1 (18.7 to 18.9 kcalmol 1 ) are in ag reement with previous studies. 3.3.5.5 Viewing the loss versus temperature plots in Figure 3 1 3 (a d) merge are nonlinear, Figure 3. 11 (a d). The merge was observed for PMMA 3 kHz to 100 kHz (116 to 135 o C); PMMA Zn(II)Bpin DPP 0.0 5wt% 1 kHz to 100 k Hz (89 to 132 o C); PMMA Zn(II)Bpin DPP 0.11wt% 3 kHz to 100 kHz (95 to 130 o C) ; PMMA Zn(II)Bpin DPP 0.9w t% 3 kHz to 100 kHz (103 to 122 o C). samples had their maxima shifted slightly towards lower temperatures commensurate with increased porphyrin loading. Table 3 6 max ) frequencies shared in the cooperative relaxatio n towards lower temperatures.

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113 Table max max ) temperatures. max 100 k Hz 60 k Hz 30 k Hz 10 k Hz 6 k Hz 3 k Hz PMMA 408.1 404.2 398.2 393.2 391.2 390.2 0.05wt% 405.7 398.2 390.9 382.8 381.2 373.5 0.11wt% 403.2 396.2 390.9 383.3 380.2 376.4 0.9wt% 395.6 391.9 387.1 380.6 378.4 376.3 The Vogel Fulcher equation, Eq. 3. 10 of the relaxation time Zn(II)Bpin DPP composites [62] ( Eq. 3. 10 ) : 1 ) o : extrapolated relaxation time at infinite temperature. T o : temperature where extrapolated relaxation time diverges. D : measure of fragility related to depths and density in the minima in the potential energy landscape of the glass former. Use of the Vogel region. Analysis using the V o temperatures (K) and o (s 1 ) with increasing porphyrin content. Figure 3. 1 5 ( a d ) s how the V F fitted plots using Eq. 3. 10 while Table 3. 7 lists the V F fitting parameters.

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114 Figure 3.15(a). Figure 3 1 5 (b)

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115 Figure 3.15(c). Figure 3 1 5 (d) Figure 3.15 Vogel Fulcher relaxation times versus temperature (K) merge region (a) PMMA, (b) PMMA Zn(II)Bpin DPP 0.05wt%, (c) PMMA Zn(II)Bpin DPP 0.11wt%, and (d) PMMA Zn(II)Bpin DPP 0.9wt%.

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116 Table 3.7. Vogel Fulcher fitting parameters for PMMA and PMMA Zn( II)Bpin DPP composites. T O (K) o (s 1 ) D R 2 PMMA 369 2.76E 08 0.450 0.999 0.05 wt% 325 6.01E 08 1.000 0.9976 0.11 wt% 313 3.09E 10 2.432 0.999 0.9 wt% 310 7.05E 14 4.375 0.984 3.3 5. 6 Viscoelastic to Conductivity Relaxation Argand plots were created to track the viscoelastic to conductivity region. An Argand plot allows for the analysis of complex plane, or g raphing with imaginary values. Specifically, Argand plots are the graphical representations of an imaginary axis (y ordinate) orthogona l to a real axis (x abscissa). electric loss modulus) is the imaginary component plotted on the ordinate axis (y) modulus) is the real component p lotted on the abscissa axis (x). From these plots, the dielectri c strength, interfacial polarization present (electrode sample), average relaxation time ( ), viscoelastic influence on mechanism of conduction, and ideality of the polymer ion translational properties can be determined. It should be noted that with Argan d plots while the high frequency is on the right side. As the samples were heated approaching Tg, it can be seen in Argand plots that the interfacial polarization from the electrode (non origin intercept) lessens, Figures 3 1 6 ( a c ) Interfacial polarization manifests as a non origin (0,0) intercept [28] This p hysically means there is a barrier of electron flow from the electrode and the sample. The reduced interfacial polarization results from the increased free volume which facilitates improved relaxation times and lessens the current flow barrier between het erogeneous items.

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117 As seen in Figure 3. 1 6 (b) a transition between viscoelastic and conductivity relaxatio n mechanisms begin to manifest a t 60 C. At temperatures higher than Tg, the viscoelastic effects upon conductivity are limited, as discussed below. However, at this temperature viscoelastic effects within th e polymer are still observed. The character of the conduction mechanism changes as the temperature is increased. The split manifests in a low frequency (left side) and high frequency (right side) influence which is st ill a function of temperature. At lower temperatures (
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118 In Figure 3. 1 6 (d) PMMA Zn(II)Bpin DPP 0.9 wt% sample is shown and semicircles are added for v isual aid for the low frequency conductivity rel axation mechanism (left side), and the high frequency viscoelastic condu ction mechanism (right side). Note that the total conduction at these temperatures would still be described as combination of these two events which is repres ented by the outer semicircle. In this region, there will be two predominate average relaxation times, for each process. As the temperature is increased, the viscoelastic effects are made negligible and the conductivity mechanism predominates in the sample. Figure 3. 17 shows at 155 C only one arc is observed with a low frequency origin intercept, thus revealing a predominant conductivity relaxation. Figure 3.16(a).

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119 Figure 3 1 6 (b) Figure 3.16(c).

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120 Figure 3 1 6 (d) Figure 3 1 6 A (a, b, and c) PMMA c ontrol and PMMA Zn(II)Bpin DPP composites in respective wt%s (w/w) at 25, 60, and 105 C, respectively. (d) PMMA Zn(II)Bpin DPP 0.9 wt% with overlaid semicircles for low, high, and combined low high p lots showing transition in conduction mechanism. 3. 3 .5. 7 Conductivity Relaxation for the resolution of the viscoelastic process form the conductivity effects. Essentially, E q. 3 8 allows the space charge effects to be suppressed revealing the ionic co nductivity peaks [16, 22, 27] relaxation is not typically seen fully resolved in PMM A after the electric modulus formalism due to its weak intensity and cooperat Four proofs exist to confirm ionic conductivity relaxations [21, 27, 28] The first proof, Argand plots demo nstrate that viscoelastic effects from the polymer are minimized. The second proof is a comparison of our samples to ideal ionic translation The third proof, AC conductivity, demonstrates no frequency dependence upon sample

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121 conductivity revealing true c onductivity relaxations. The fourth and final proof compares DC ) peaks and the electric loss r apparent E a ; agreement in both denotes conductivity relaxation [63, 64] 3. 3.5. 7.1 Proof 1 Argand Plots r, Eq. 3. 5 and Eq 3. 6 for a single relaxation time. Cole and Cole [65] R U )/2 is obtained. With frequencies. Semicircular behavior is characteristic of Debye behavior for small rigid mo lecules and molecular liquids [56, 57] When a semicircle arc is observed in these plots, it indicates that v iscoelastic relaxations are not present and only the effects from the conductivity relaxations are observed. The ideal semicircle arc can be represented by the Debye semicircle equation, E q. 3. 11 whe n above the Tg of the polymer. ( Eq. 3. 11 ) M : Electric Modulus at high frequency M S : Electric Modulus at zero frequency Polymers can deviate from this ideal behavior and exhibit skewed semicircles since they can have a distribution of relaxation times. Often due to this factor, polymers

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122 can be evaluated using a modified Debye equation: Cole Cole (C C), Cole Davidson (C D), or Havriliak Negami (H N) [30, 65, 66] The modified Debye equations account for non ideal behavior whic h is commonly encountered in polymer conductivity because they are not dilute polar solutions. Figure 3. 1 7 shows an Argand (complex plane) plot of PMMA control and PMMA Zn(II)Bpin DPP composites at 155 C and 200 C. These plots exhibit semicircle behavior within this region signifying the absence of viscoelastic relaxations. From these Argand plots, the dielectric relaxation str ength can be calculated using Eq 3. 12 The dielectric relaxation strength is a measure o f the alignment of dipoles within the sample and is listed in Table 3. 8 All samples increased in dielectric strength with increasing temperature. The best dipole alignment occurs with the 0.05 wt% sample at temperatures below 180 C. At 180 C, it appe ars that the added thermal energy allows for the 0.9 wt% sample to obtain higher alignment. Indicating that greater porphyrin content may be hindering the orientation of dipoles within the sample (below 180 C), but still increases its overall conducti vit y (S/m) as discussed below. This presumably occurs as the enthalpy increase affords greater free volume within the sample allowing for better dipole reorientation to matc h the applied electric field. It remains unclear why the 0.11 wt% sample was anomalo us to the macro trend, but we speculate on this later. ( Eq. 3.12 )

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123 Figure 3. 1 7 200 C. Semicircle behavior denotes minimization of viscoelastic effects. Semicircles shown in graph are a visual aide only. Table 3.8. Dielectric relaxation strengths ( M) of samples tested. 155 C 180 C 200 C PMMA 0.221 0.241 0.268 PMMA Zn(II)Bpin DPP 0.05wt % 0.233 0.253 0.285 PMMA Zn(II)Bpin DPP 0.11wt % 0.225 0.250 0.271 PMMA Zn(II)Bpin DPP 0.9wt % 0.229 0.270 0.310 3. 3.5. Starkweather and coworkers showed that at temperatures above the Tg s (low frequency relaxed state) which is independent of 0 (at a given temperature) [28] Under these conditions, the complex permittiv ity, E q. 3. 4 is given by the following E q. 3. 1 3

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124 ( Eq 3. 1 3 ) : Complex permittivity S 0 0 : ionic conductivity Starkweather et al then applied this to the electric mod ulus in the following Eqs. 14 and 15 respectively. ( Eq. 3 1 4 ) ( Eq. 3 1 5 ) Where the characteristic time, Eq 3. 1 6 and an electric modulus M S Eq. 3 1 7 are defined as: ( Eq. 3. 1 6 ) ( Eq 3. 1 7 ) Between 0.1 Hz to 100 0 Hz graphing plots o Eq 3 1 4 will exhibit an ideal slope of 2; and in plots Eq. 3. 1 5 will exhibit an ideal slope of 1. Starkweather plots, Figures 3. 1 8 (a d) show that all samples approach the ideal values of 2 or 1 respectively, confirming the start of the conductivity region (absence of viscoelastic effects) at 155 C proving the observed relaxations are due to ionic conductivity.

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125 Figure 3.18(a). Figure 3 1 8 (b)

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126 Figure 3.18(c). Figure 3 18 ( d ) Figure 3.18. Starkweater plots PMMA and PMMA Zn(II)Bpin DPP composites. (a d). ) versus log frequency (Hz) plots for samples at 155 C. Ideal slopes (m) for ( ) and ( ) are 2 and 1, respectively.

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127 3. 3.5. 7.3 Proof 3 AC conductivity When viscoelastic effects are negligible, t he loss factor is described by E q. 3. 7 AC ) can be obtained E q. 3. 1 8 Figures 3 1 9 ( a d ) AC versus the log of frequency (Hz) for temperatures above Tg, conductivity is predominant for our samples. ( Eq. 3. 1 8 ) AC is the sum of all dissipative effects including DC DC ) caused by the translation of ions as well as the dielectric loss dispersions [67] Increasing the frequency results in a mean displacement of the charge carriers, and after a critical frequency (f c ) the re al part of conductivity follows a power law relations hip at a constant temperature, E q 3. 1 9 [67, 68] ( Eq. 3. 1 9 ) DC A and s s parameters that depend upon temperatu re, morphology, and composition [67, 68]

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128 Figure 3.19(a). Figure 3 1 9 (b)

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129 Figure 3.19(c). Figure 3 1 9 (d). Figure 3 1 9 AC ) (S/m) versus frequency (Hz): between 130 to 270 C. (a) PMMA Control. (b) PMMA Zn(II)Bpin DPP 0.05 wt% (w/w). (c) PMMA Zn(II)Bpin DPP 0.11 wt% (w/w). (d) PMMA Zn(II)Bpin DPP 0.9 wt% (w/w). AC begins to show a plateau ( ca. 155 C) from 10 1 to 10 3 Hz, signifying the beginning of the conductivity relaxation region Figure 3 1 9 (a d). AC plateau then expands to include higher frequencies 10 3 to 10 6 Hz as the temperature is increased, thus the illustrating frequency independent conductivity relaxation region. The absence of the frequency dependence upon conductivity is the

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130 observa tion that signifies neg ligible viscoelastic effects. The low frequency plateau begins in the low frequency regime first because the alternating field provides sufficient time for charge carriers to t ranslate over larger distances. As the temperature is i ncreased, the higher frequency alternating fields begin to achieve an almost constant value joining the plateau. This analysis reveals the conductivity relaxation region to exist between 160 to 190 C. Samples containing Zn(II)Bpin DPP had approximately 15 AC values than that of the control PMMA. 3.3. 5. 7. 3.1 DC Conductivity AC DC ) was obtained by extrapolation to zero frequency. This may be accomplished either by solving E q. 3 1 9 DC or following the convention of using the lowest frequency tested (<1 Hz) as the y axis intercept when ( ) [67, 68] Choosing the latter is only applicable when the low frequency end ( ca. 10 1 to 10 3 Hz) has maintained a plateau. If these lower frequencies curve downward then sample heterogeneity or interfacial polarization between the sample and electrode are present and E q. 3 1 9 should be utilized. DC follows the A rrhenius relationship shown in E q. 3 20 DC increased with increasing temperature and incre asing Zn(II) Bpin DPP content. Figure 3 20 shows DC versus temperature for all samples within the conductivity region. Again the PMMA Zn(II)Bpin DPP 0.11 wt % sample is anomalous with the respect to the DC values, mirr oring the dielectric strength.

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131 ( Eq 3 20 ) E a : : Activation Energy R: : Ideal gas constant DC : DC conductivity 0 : : Pre exponential factor (conductivity at infinite temperature) Figure 3 20 DC conductivity (S/m) versus temperature (C) for PMMA, PMMA ZnBpin DPP 0.05 wt%, PMMA ZnBpin DPP (0.11 wt%), and PMMA ZnBpin DPP (0.9 wt%). DC versus inverse temperature (140 to 210 C); Figure 3 21 shows the plots for PMMA control and PMMA Zn(II)Bpin DPP composites. Apparent E a d ecreased with i ncreasing wt% of porphyrin. The addition of the Zn(II)Bpin DPP lowered the apparent E a DC from 150.8 to 98.1 kJmol 1 (36 to 23.4 kcalmol 1 ). This conforms to previous studies which have reported neat PMMA E a DC values of 54.3 to 152 kJmol 1 (12.9 to 36.3 kcalmol 1 ) [19, 20, 36] Apparent E a DC values are presented in Table 3 9.

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132 Figure 3 21 Natural log ( ln ) DC versus inverse temperature (K) plots of PMMA Control and PMMA Zn(II)Bpin DPP composites (0.05 wt%, 0.11 wt%, and 0.9 wt%). Table 3.9. Ionic conductivity apparent E a for PMMA and PMMA Zn(II)Bpin DPP composites. E a DC kcal/mol kJ/mol PMMA 36.0 150.8 0.05 wt% 28.0 117.3 0.11 wt% 26.1 109.4 0.9 wt% 23.4 98.1 E a DC decreased with increasing Zn(II)Bpin DPP content. 3. 3.5. 7. 4 DC max ) Conductivity relaxations can be confirmed by comparing the temperature where the DC DC comparing th eir apparent E a T o confirm the rel axations above the Tg are conductivity relaxations one can plot DC max ) versus t emperature ( K ) and compar e the temperature range overlap and the E a obtained using DC Eq. 3. 20 3 9 respectively, Figure s 3 2 1 ( a d) If the temperature overlap and the apparent E a are similar then it has been shown by Pissis et al that they are confirmed conductivity relaxations [63, 64] Table 3 10 lists the

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133 apparent E a DC overlap and apparent E a for both methods provide excellent agreement as shown in Figure 3 22 (a d) The difference in the two apparent E a may come from the residual, although minimized, effects remaining from viscoelasticity.

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134 Figure 3.22(a). Figure 3.22(b).

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135 Figure 3.22(c). Figure 3 2 2 (d) Figure 3 2 2 Overlay of DC max ) versus 1000/T (K) demonstrating good temperature and E a agreement proving conductivity relaxation. (a) PMMA. (b) PMMA Zn(II)Bpin DPP 0.05wt%. (c) PMMA Zn(II)Bpin DPP 0.11wt%.(d) PMMA Zn(II)Bpin DPP 0.9wt%. DC N fu frequency (Hz) at constant temperature. The background of H N function is discussed in the next section

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136 Table 3.10. DC apparent E a E a DC E a max ) kcal/mol kJ/mol kcal/mol kJ/mol PMMA 36 150.8 35.7 149.26 0.05 wt% 28 117.3 26.8 112.5 0.11 wt% 27.3 114.3 26.8 112.3 0.9 wt% 23.4 98.1 23 96.3 C ersus temperature plot s are conductivity relaxations. 3. 3.6 Hav riliak Negami Function Havriliak and Negami modified the empirical Debye equation Eq. 3. 4 for dilute polar solutions to reflect the distribution of average relaxation times exhibited by polymer systems, Eq. 3. 21 [30 ] The Havriliak Negami (H N) equation uses two correction c semicircles in complex plane Cole C ersus ) plots. Using the H N equation to fit the conductivity relaxation peaks on e can obtain unbiased data. Specifically, the H N equation allows for the o alpha (Eq. 3. 21 ) : Complex permittivity : Permittivity (dielectric constant) : Loss factor i : ( 1) 1/2 : Average dielectric relaxation time (s 1 ) : Unrelaxed high frequency intercept ( ) 0 : Relaxed low frequency intercept ( 0 ) 0 : exponential terms to correct for skewed arc function

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137 Since this study utilized a polymer composite the complex electric modulus M*, Eq. 3 8 must be used to minimize the conductiv ity effects from the MWS effect Recall that t he complex electri c m odulus can remove the MWS effect present in polymer composites and separate the viscoelastic and conductivity relaxations [21, 59 61] Therefore it is essential to use H N equat ion in terms of the complex electric modulus M*. Appreciatively, Tsangaris et al published a detailed proof converting the Havriliak Negami (H N) equation into terms of the electric modulus for use in analysis of polymer composite systems [29] se the H N equation based upon electric m odulus back into the Debye, Cole Cole, or Davison Cole equations. [29, 56, 65, 66] The H 3 22 and Eq. 3 2 3 r espectively [29] Parameters Specificall y, represents the depression angle and is related to the limiting angle observed at the low frequency ( 0) x axis intercept loci (M o ). Visual clarification is provided in Figure 3 2 3 Parameters and can either depress or inflate the angle which alters the shape of the semicircle from ideal Debye behavior Eq. 3 8 (perfect semicircle) to match the non ideal empirical data from a composite system. Even though the conductivity region reflects minimized viscoelastic influence these skew parameter angles relate the rema in ing in fluence from the viscoelastic polymer upon t he conductivity

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138 Figure 3 2 3 (depression angle), (related to the limiting angle ), M o (low frequency) and M (high frequency) axis)) intercepts. Note that in complex plane relaxation time ( ) is intercept of line formed by ( and the complex plane trace. (Eq. 3 22 ) (Eq. 3 2 3 ) M : Unrelaxed high frequency intercept ( ) M s : Relaxed low frequency intercept ( 0 ) : Skew adjustment.

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139 Where A Eq. 3 2 4 and (limiting angle) Eq. 3 2 5 are defined: (Eq 3 2 4 ) (Eq. 3 2 5 ) 3 22 and Eq. 3 2 3 respectively for the conductivity relaxation region of 160 to 190 C. As expected the frequency maxima shifted to higher frequencies with increasing temperature amongst all samples. Figure 3 2 4 ( a h ) illus trates overlaid H C and 190 C for all samples tested. Table 3 11 lists the H N fitted parameters, defined above, for PMMA and PMMA Zn(II)Bpin DPP composites at 160 C, also including dielectric strength Eq 3 12 A full list of H N fit parameters from 160 to 190 C for all samples tested are provided in Tables 3 12( a d). Table 3.11. H N fit parameters for PMMA and PMMA Zn(II)Bpin DPP composites 160C. H N parameters 160 C M S M (s 1 ) f MAX (Hz) PMMA 3.90E 03 0.2258 0.6392 1.1698 8.61E 03 18.48 0.2220 0.05 wt% 6.12E 04 0.2330 0.4203 1.1474 3.08E 03 51.6 0.2324 0.11 wt% 3.03E 03 0.2250 0.7081 1.1673 4.88E 03 32.6 0.2220 0.9 wt% 5.45E 04 0.2336 0.5519 1.1546 1.63E 03 97.16 0.2331 In the max ). The order maintained: PMMA < 0.11 wt%, < 0.05 wt% < 0.9 max ) at each isotherm, respectively. Figure 3 2 5 showing the observed order at 160 C. Since ( max ) is inversely proportional to the

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140 trend is maintained as mentioned above but inverted with respect to time (s 1 ). This specific order elution may be related to th e minimal porphyrin porphyrin interactions observed by the fluorescence lifetimes in the amorphous composite samples Figure 3.24(a). Figure 3 2 4 ( b )

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141 Figure 3.24( c). Figure 3. 24 ( d )

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142 Figure 3.24( e). Figure 3 2 4 ( f )

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143 Figure 3.24( g). Figure 3 2 4 ( h ) Figures 3 2 4 Hav riliak relaxation plots 160 and 190 C (a and b) PMMA, (c and d) PMMA Zn(II)Bpin DPP 0.05wt%, (e and f) PMMA Zn(II)Bpin DPP 0.11wt%, (g and h) PMMA Zn(II)Bpin DPP 0.9wt%.

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144 Figure 3 2 5 max ) order PMMA < 0.11 wt% < 0.05 wt% < 0.09 wt%. The following Tables 3 12( a d ) provide the parameters obtained from an unbiased Havriliak Negami fit on PMMA and PMMA Zn(II)BpinDPP composites. Table 3 12(a) H N parameters 160 to 190 C for PMMA. PMMA ( C) M S M 1 ) f MAX (Hz) 160 3.90E 03 0.2258 0.6392 1.1698 8.61E 03 18.48 2.22E 01 165 4.04E 03 0.2274 0.7745 1.1721 5.06E 03 31.46 2.23E 01 170 2.93E 04 0.2302 0.2783 1.1636 3.10E 03 51.27 2.30E 01 175 4.97E 04 0.2337 0.5113 1.1660 1.95E 03 81.46 2.33E 01 180 4.62E 04 0.2376 0.5944 1.1772 1.27E 03 125.07 2.37E 01 185 3.78E 04 0.2419 0.6335 1.1856 8.52E 04 186.7 2.42E 01 190 1.42E 04 0.2477 0.5395 1.1867 5.85E 04 272.05 2.48E 01

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145 Table 3 12(b) H N parameters 160 to 190 C for PMMA Zn(II)BpinDPP 0.05wt%. 0.05wt% ( C) M S M 1 ) f MAX (Hz) 160 6.13E 04 0.2330 0.4202 1.1473 3.08E 03 51.66 2.32E 01 165 3.22E 04 0.2361 0.4007 1.1525 2.01E 03 79.01 2.36E 01 170 3.95E 04 0.2400 0.5344 1.1635 1.38E 03 115.43 2.40E 01 175 3.32E 04 0.2448 0.5772 1.1761 9.85E 04 161.5 2.45E 01 180 1.68E 04 0.2509 0.5243 1.1838 7.23E 04 220.27 2.51E 01 185 2.21E 04 0.2582 0.6091 1.1864 5.49E 04 289.92 2.58E 01 190 1.67E 04 0.2665 0.6073 1.1866 4.15E 04 383.53 2.66E 01 Table 3 12( c ) H N parameters 160 to 190 C for PMMA Zn(II )BpinDPP 0.11 wt%. 0.11wt% ( C) M S M 1 ) f MAX (Hz) 160 3.03E 03 0.2250 0.7081 1.1673 4.88E 03 33 2.22E 01 165 4.01E 03 0.2278 0.8456 1.1669 3.32E 03 47.99 2.24E 01 170 4.11E 04 0.2316 0.4325 1.1648 2.31E 03 68.87 2.31E 01 175 2.60E 04 0.2364 0.4249 1.1685 1.66E 03 96.11 2.36E 01 180 1.51E 04 0.2425 0.4086 1.1767 1.18E 03 134.47 2.42E 01 185 1.59E 04 0.2493 0.4489 1.1814 8.61E 04 184.81 2.49E 01 190 2.00E 04 0.2563 0.5677 1.1820 6.36E 04 250 2.56E 01 Table 3 12( d ) H N parameters 160 to 190 C for PMMA Zn(II)BpinDPP 0.9wt%. 0.9wt% ( C) M S M 1 ) f MAX (Hz) 160 5.45E 04 0.2336 0.5519 1.1546 1.64E 03 97.16 2.33E 01 165 5.30E 04 0.2379 0.6017 1.1699 1.34E 03 119.16 2.37E 01 170 3.66E 04 0.2487 0.5790 1.2106 1.02E 03 156.64 2.48E 01 175 1.17E 04 0.2534 0.4584 1.1840 7.58E 04 209.88 2.53E 01 180 1.42E 05 0.2641 0.1861 1.1842 5.62E 04 283.36 2.64E 01 185 1.40E 05 0.2641 0.2310 1.1842 4.11E 04 387.46 2.64E 01 190 1.33E 03 0.2856 0.9262 1.1848 2.94E 04 541.09 2.84E 01

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146 3. 3.7 Tangent of Dielectric Loss Angle An ideal capacitor (condenser) of geometric capacitance, C 0 where polarization is instantaneous the charging (capacitive) current is 90 0 out of phase and is defined in Eq. 3. 26 [3 1] In a capacitor where absorptive polarization occurs the current also has a component Eq. 3. 27 [31] The ohmic loss current measures the absorption from the dissipation of part of the energy of the field as heat [31] (Eq. 3. 26 ) (Eq 3. 27 ) E : External Applied electric field : dielectric constant (permittivity) : loss factor C o : Reference capacitance. The vector sum of the charging and loss currents Eq. 3. 26 and Eq. 3. 27 yields vector amplitude for the charging current Eq. 3. 26 Fig ure 3. 26 direct measurement of the dielectric loss and is calculated using Eq. 3. 28 [31] Therefore between the resistive ( lossy) and reactive (lossless) component s in response to an applied electromagnetic field. 3. 13 3 27 ( a d ) are provided for discrete frequencies: 1 Hz, 60Hz, 100Hz, and 100 kHz. These repo rted electric field frequencies in addition to providing a wide range (10 6 decades) are of specific interest because they are commonly used in electronics and reported in literature. Furthermore, the tan frequencies are evaluated at their peak height ma x

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147 ( max ) which clarifies the thermal locations of the dissipation factor maxima, which is also important for electronic applications. Figure 3. 26. Current voltage diagram of a dielectric showing loss. (Eq. 3 2 8 ) Tan of PMMA manifests from the [ (C=O)OCH 3 ] pendant group reorientation to the applied electric field [69] For this series tan is observed to increase the greatest with the addition of 0.05 wt% Zn(II)Bpin DPP then drop lower after increased loadin g yet still trending an upward increase over PMMA for 0.11 wt% and 0.9wt% Therefore, the largest dissipation factor increase results from the least level of loading when in the relaxations at higher porphyrin loading levels above 0.05 wt%. The r estricted levels of porphyrin content (0.11 and 0.9 wt%) do not reorient to the applied electric field due to steric hindrance from reduced free volume presumably due to the lower temperature (
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1 48 Tan peaks at 100 kHz (117 to 130 ted to the Tg of PMMA. Here the [13] Tan region increa sed directly with the increased loading levels of the Zn(II)Bpin DPP while decreasing the temperature where the peak maxima occur. The uncoupled relaxation and the antiplastization effect due to the porphyrin is masked when the relaxation merges with the relaxation. Zn(II)Bpin DPP composites. 1 Hz 60 Hz 100 Hz 100 k Hz C C C C PMMA 0.0431 7.3 0.0528 45.0 0.0541 49.5 0.1318 130.5 0.05 wt% 0.0504 4.4 0.0618 42.3 0.0637 48.2 0.1317 121.9 0.11 wt% 0.0446 9.3 0.0567 46.9 0.0587 47.2 0.1333 120.9 0.9 wt% 0.0475 2.1 0.0592 39.3 0.0613 44.8 0.1343 117.0 Thus the macro trend observed is that the porphyrin increases the dissipation factor value as the observed tan ( max ) moves to lower temperatures. The dissipation factor values become more greatly aligned to porphyrin wt% loading as the frequency is increased because these peaks occur at higher temperatures affording greater free volume allowing for greater orientation to the applied electric field.

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149 Figure 3.27(a). Figure 3 27( b ).

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150 Figure 3.27(c). Figure 3 27( d ) Figure 3 27. Tan versus temperature ( C) for PMMA and PMMA Zn(II)Bpin DPP composites (a) 1Hz, (b) 60 Hz, (c) 100 Hz, and (d) 100 k Hz.

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151 3.3. 8 PMMA Degradation 3.3. 8 .1 Unzipping of PMMA (Thermal degradation) In this study, samples were brought up to 270 C for dielectric analysis to further DEA understanding of PMMA be yond 190 C, a common high temperature stop point in literature. The increased high temperature endpoint would allow for investigation of the thermal degradation of PMMA using DEA. In the temperature region of ca. 215 to 220 C frequency independent maxima were ob reaching a maximum peak height value at 0.3 Hz as shown in the versus temperature for PMMA and porphyrin composite s Figures 3 2 8 (a h ) This temperature region is associated with the unzipping of PMMA and may represent individual monomer repeat units in the initial process of degradation. The temperature at which this occurs corresponds to the first of a two part th ermal degradation process. This first process vinylidine chain ends, Figure 3 2 9 a process that has been previously observed using thermogravametric analysis (TGA) and FT IR [47, 70, 71]

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152 Figure 3.28(a). Figure 3 2 8 (b )

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153 Figure 3.28(c). Figure 3. 2 8 (d)

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154 Figure 3.28(e). Figure 3. 2 8 (f)

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155 Figure 3.28(g). Figure 3 2 8 ( g ) Figure 3 2 8 Frequency independent maxima of p versus temperature ( C) (a&b) PMMA. (c&d) PMMA Zn(II)Bpin DPP 0.05wt%.(e&f) PMMA Zn(II)Bpin DPP 0.11wt% (g&h) PMMA Zn(II)Bpin DPP 0.9wt%. Frequency independent regions when voltage is held constant have been observed in DEA analysis of systems where com ponents are in separate phases [72] Coincidently, these regions look similar to goldstone relax ations. It should be noted that the goldstone relaxations occur from increasing applied voltage which then uncoils the

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156 polymer chain ultimately decreasing the loss modulus peak int ensity [58, 73] Since the voltage in the TA 2970 is held constant, the observed frequency independent region is not of goldsto ne origin, but is caused by a phase change. These observations allow us to assign this area to the degradation process where the PMMA is unzipping, which regenerates the methyl methacrylate monomer (MMA). Upon degradation, the MMA monomer is then volatil ized into the gas phase separating itself from the solid composite. The degradation process onset temperature remained independent of Zn(II)Bpin DPP content. Figure 3 2 9 Poly(methyl methacrylate) thermal degradation via end group scission schematic 3.3. 8 .2 PMMA Degradation Electric Modulus Investigating the degradation temperature region after applying the electric modulus formalism has revealed interesting results. Recall that the application of the electric modulus reduces the MWS effect allowing insight into the molecular relaxations of the polymer by removi ng the effects form MWS effect. Traditionally, it is expected to see the average relaxation time to decrease with increasing temperature. Since is inversely proportional to the observed ( max ) is shifted to higher (increased) frequencies as the temperature is elevated. This has been observed in prior studies of methacrylate polymers [20, 24, 36]

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157 What is unique in this study is that the is seen to decrease in time (s 1 ) up to the point of an observed minimum of ca. 220 C then increase beyond that temperature to 250 C. Note that 220 C is the reported temperature for the first s tep of PMMA degradation [46] Figure 3 30 (a d) shows the observed relaxation times decreasing through the conductivity region reaching a minimum at ca. 220 C then increasing again as the temperature is increased. Figures 3 30 ( b d) represent the PMMA porphyrin composites and as such it is evident that the presence of the porphyrin has an effect on degradation that cannot be fully answered in this experiment, yet all composites show similar behavior as the control. It is the primary focus to concentrate upon the PMMA control in terms of degradation due to the complexities that presumably occur with the addition of the metalloporphyrin . Furthermore, this is illustrated in Figures 3 31 (a ) and ( b) max ) versus log frequency (Hz) In Figure 3 31 (a) the maxima continue towards higher frequencies from 195 to 220 C and then maxima begin to manifest at lower frequencies from 220 to 250 C, Figure 3 31 (b)

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158 Figure 3.30(a). Figure 3 30 (b)

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159 Figure 3.30(c). Figure 3 30 ( d ) Figure 3 30 Average relaxation time, versus temperature ( C) from the conductivity region (160 to190 C) and beyond to first part of PMMA degradation (190 to 27 0 C) (a) PMMA, (b) PMMA Zn(II)Bpin DPP 0.05wt.%,(c) PMMA Zn(II)Bpin DPP 0.11wt.%, and (d) PMMA Zn(II)Bpin DPP 0.9wt.%

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160 Figure 3.31(a). Figure 3 31 (b) Figure 3 31 ersus log frequency (Hz) for PMMA (a) 195 to 220 C (b) 220 to 2 50 C.

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161 3. 3. 8 .3 PMMA Degradation AC Conductivity AC increased with temperature up to ca. 220 C. At this AC values decreased slightly presumably due to the decomposition of PMMA to MMA where phase separation occurs and presumably leads to a disruption of ionic flow. Again the addition o AC in a complex manner where the macro trend lowered the conductivity near 220 C. The nature of the decrease AC in PMMA porphyrin samples indicates a complex process which cannot be adequately addressed in this st udy, therefore inspection of the control is the focus in the inquiry to DEA spectra with respect to PMMA degradation. Noting the complexity aforementioned ; PMMA AC approximately 220 to 250 C where then the heavier loaded samples (0.11 wt% and 0.9 wt%) increased AC beyond that to 270 C possibly indicating alternative more complex degradation pathways interacting with PMMA, Figure 3 3 2 (b d). Figure 3 3 2 (a) illustrates the AC cond uctivity of PMMA 220 to 270C

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162 Figure 3.32(a). Figure 3 3 2 (b)

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163 Figure 3.32(c). Figure 3. 3 2 (d). Figure 3 3 2 AC (S/m) versus log frequency (Hz). (a) PMMA, (b) PMMA Zn(II)Bpin DPP 0.05wt.%, (c) PMMA Zn(II)Bpin DPP 0.11wt.%,(d) PMMA Zn(II)Bpin DPP 0.9wt.%.

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164 3.4 Conclusion Optically transparent composite films were made of PMMA and Zn(II)Bpin DPP then analyzed via DEA, DSC, UV vis and fluorescence spectroscopy. Calculation of the dipole of Zn(II)Bpin DPP was found to be 2.87 Debye on an optimized structure. The vector points from the Zn center to the boron containing substituent. Fluorescence spectroscopy in both steady state and time resolved emission results indicate a monodisperse population of porphyrin within the polym er matrix at all loading conditions examined. Permittivity of the PMMA composites increased with increasing porphyrin content and further increased with increasing temperature. This increase in permittivity had a maximum limit beyond which no additional increase was observable beyond 0.11 wt% of Zn(II)Bpin DPP loading at STP DSC showed that Zn(II)Bpin DPP acted as an antiplasticizer increasing the Tg with increasing wt%. loading of porphyrin. The employment of the electric modulus formalism allowed for the separation of viscoelastic and conductivity relaxations. This allowed for the study of the effects of increased loading of Zn(II)Bpin DPP on and conductivity relaxations. The relaxation showed no appreciable change in apparent activation energy E a The conductivity relaxation showed a decrease in apparent activation energy, E a Th e conductivity region (1 60 to 190 C) was confirmed through four proofs. AC AC was shown to increase in all samples with increasing temperature. AC showing an increase in conductivity, up to 15 times greater over the PMMA control.

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165 With the exception of the PMMA D C and dielectric strength increased with increasing temperature and increasing wt% of porphyrin. However, the E a DC calculated values followed the trend of decreasing the activation energy with increa sing Zn(II)Bpin DPP content. Since only the PMMA Zn (II)Bpin DPP 0.11 wt% had exceptions relating to ion translation, it is speculated that through fluorescence spectroscopy there may be a weak porphyrin porphyrin interaction that relates to percolation theory with respect to charge carrier motion This study is believed to be the first to inspect the first part of degradation of PMMA using DEA. A frequency independent region was observed around 220 C. This correlates with the degradation of the PMMA into MMA monomer repeat units. The phase separ ation of the polymer and gaseous MMA is believed to be the source of the frequency independent region. AC was observed to decrease in this unzipping region most likely a result of the disruption of ionic carrier flow through the samples due to phase sepa ration. Additionally, this composite offers interest in electrical applications since the added porphyrin uniquely raises the Tg affording improved thermal stability while simultaneously m aking ion translation easier. H N analysis of the conductivity rel axation region (160 to 190 C) allowed for max ) order seen was in agreement with loss factor analysis in previous work. The PMMA Zn(II)Bpin max ) to shift towards a hi gher frequency than ex pected. Average relaxation times, max ) order. max ) and revealed an interesting observation of increase in the rel axation time (decreasing( max )).

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166 Tan dissipation from the lowest level wt% loading of Zn(II)Bpin DPP, 0.05wt%. The tan relaxation then followed with the wt% loading resulting in the 0.9wt% sample to have the highest dissipation factor. Thus revealing how the additional free volume upon the samples affects dissipation factor. 3. 5 Acknowledgements We would like to thank Kari Fowler of Georgia Pacific Atlanta Georgia USA for supplying material support of our continued research in dielectric analysis. We extend our thoughts and prayers to her family. This research was made possible through funding from the Department of Defense under grant HDTRA1 08 0035. 3. 6 References 1. Chen Y and Zhang XP Journal of Organic Chemistry 2003;68(11):4432 4438. 2. Gao GYY, Chen Y, and Zhang XP Journal of Organic Chemistry 2003;68(16):6215 6221. 3. Gao GY, Colvin AJ, Chen Y, and Zhang XP Organic Letters 2003;5(18):3261 3264. 4. Gao G Y, Chen Y, and Zhang XP Organic Letters 2004;6(11):1837 1840. 5. Gao GY, Colvin AJ, Chen Y, and Zhang XP Journal of Organic Chemistry 2004;69(25):8886 8892. 6. Chen Y, Gao GY, and Zhang XP Tetrahedron Letters 2005;46(30):4965 4969. 7. Gao GY, Ruppel JV, Allen DB, Chen Y, and Zhang XP Journal of Organic Chemistry 2007;72(24):9060 9066. 8. Ruppel JV, Jones JE, Huff CA, Kamble RM, Chen Y, and Zhang XP Organic Letters 2008;10(10):1995 1998. 9. Zhu SF, Ruppel JV, Lu HJ, Wojtas L, and Zhang XP Journal of the American Chemical Society 2008;130(15):5042 +.

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171 CHAPTER 4 : FUTURE WORK 4.1 Contributions of Dissertation This dissertation has allowed investigation into polymer dye relationships while being subjected to an electric field. The experiments were exciting and have offered new directions MALDI TOF, Nanoliter and Nanoliter electret synthesis, and a more complete picture of the electrical structure property relationsh ip of a polymer and porphyrin. Even with this good start there are many more questions and projects to explore arising for the successful research pre sented here. T he following are ideas for advancement of research presented in this dissertation Th e future ideas shall be presented in the order as they were addressed previously 4.2 MALDI TOF with Induction Based Fluidics. In our experiments we ran the synthetic polymers in linear mode, a common method to ascertain digested peptides as is done in proteomics. The experiment can be recreated as outlined in Chapter 1, but changing the linear mode of the MA L DI TOF to reflection mode. From this the polymer chain end groups could be analyzed as is the academic standard and IBFs impact upon resolution could be better understood

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172 To further separate the new proposed project polymers should be synthesized i n our lab that are not of narrow molecular weight. Radical chain and condensation polymers should be investigated as well with dendrimers, block c o polymers, and novel polyurethanes within our lab The MALDI TOF results could be easily compared to micropipette dried droplet and further compared to gel permeation chromatography (GPC), a relative standard to determine number and weight average molar mass. From a conscious selection of polymers it ma y be possible to determine trends for which environments are most beneficial to IBF thus raising spectra quality even further in this field leading to optimization standards for samples prepared with IBF If trends can be identified the mechanism of act ion for this enhancement will be put into focus. Finally, t he electret double layer enhancement effect/electric fi e ld effect could allow for matrix sources (laser dyes) that have not been used in prior studies opening possibilities for new MALDI TOF reci pes. 4.3 Electret s and monodisperse spheres. The IBF apparatus opens up a unique ability to rapidly create spherical electrets at desired nano volume s The initial try was not successful, but left us with information and data on how to proceed anew to create the desired target. Since our principal idea i s based upon freezing in the electric double layer this can still be implemented and new suggestions are offered. Firs t it would be wise to retry the 2 HEMA electrets using less initiator. Dropping the initiator from 2.0 towards 0.2 wt% should allow for higher quality poly(2 HEMA) synthesis which would have a high Tg eliminating a possible rea son f or failure ; that the lowe r Tg allowed for molecular relaxations thus allowing charge migration Next, the addition of a crosslinker ethylene glycol dimethacrylate (EGDMA) or any of its extended

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173 analogs or even branched such as trimethylpropane trimethacrylate Figure 4.1, could restrict the movement of the polymer chains possibly locking electret charges in place. Since 2 HEMA is hydrophillic when polymerized it may be necessary to find a polymer that is hydrophobic so ambient humidity will not destroy the e lectret after successful synthesis as was possibly seen in the very few successful poly(2 HEMA) electrets made. With that observation it might be wise to change out the frozen CO 2 to obtain better laboratory temperature control Figure 4.1 C ross linking molecules for p oly (2 HEMA) electrets. Since dry Ice was the source to freeze monomers after IBF kinetic launch, and it s temperature i s around 80C it would be convenient to find monomers that froze in this region, but not necessary. Using a thermo electric cooling plate called a Peltier plate is recommended The Peltier plate is low cost and can provide controlled cooling up to 70 used For example an apparatus could be assembled where dry ice cools liquid acetone ( m.p. 94 C) and the acetone is used in the Peltier p late cooling apparatus as the heat source, potentially providing a cool flat surface to temperatures as low as 160 C. This could allow other monomers to be utilized. Beyond common monomers used in polymer characterization/ synthesis labs such as our s, it would be beneficial to address the possibility of photodimerization in the

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174 solid state as researched by Schmidt [1] Schmidt work exhibits many polar groups containing central doub le bonds that undergo sp2 to sp3 hybridizatio n in the solid phase using UV light. This could allow for success in t his endeavor. Two highlighted examples are presented in Figure 4.2 where the alignment afforded by IBF may lead to electrets. We have demonstrated that the IBF can kinetically launch targets into liquids when the capillary tube from the IBF apparatus is submerged. Furthermore we have seen HEMA into the oil phase when submerged produces a droplet out of phase with the surrounding oil solution. It is not known if t his droplet still has electret qualities but this could be investigated in addition to the following future work. Alternatively, Zourob et al. developed a mircoreactor to produce un iform polymer beads through a controlled flow rate [2] Size control and generation of assembly line modified to accept the IBF apparatus. Figure 4.2 C innamic acid photodimerization in solid state. (a) Hea d to tail assembly packing then photo dimerization. (b) Potentially IBF orientated cinnamic acid solid state photo dimerization that could lead to permanent electret formation, alone or in conjunction with polymer.

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175 4.4 PMMA Zn(II)Bpin DPP We observed antiplastization effects of the Zn(II)Bpin DPP porphyrin while in composite with PMMA. These effects were either masked by the large beta relaxation or a possible coordinative bond exists betweenthe porphyrin and the polymer. This bond may be sufficiently liable and disrupted in the applied electric field when under DE A Presented here is an experiment to investigate if there may be some, yet minimal interaction between the empty orb itals of the boron containing b oroester group and a moiety of PMMA. To test this dynamic mechanical a nalysis (DMA) wou ld allow us to obs erve if there were any local Van der Waa ls interactions occurring between the porphyrin and the PMMA through the study of mechanical relaxations This could further explain why the duality is present between dielectric data and thermal data where DEA dat a tends to show plasticization and DSC data show antiplasticization resulting from either mere overlap obfuscation or possibly a weak porphyrin polymer Van der Waals interaction Additionally, this experiment was devised to ultimately detect a sequestered nerve agent analog molecule diisoproply methyl phosphonate (DIMP), within a polymer matri x via the DEA Unfortunately, PMMA was not porous enough to allow the target analyte to diffuse to the target porphyrin. In the future more porous polymers such as; 2 hydroxyethyl methacrylate( 2 HEMA ) N vinyl 2 pyrrolidone (VP) and 2,3 dihydroxyproply methacrylate (DHPMA) should be investigated, Figure 4.3 Note that most porphyrins diffuse out of the previous polymer matrices and covalent bonding of the porphyrin may have to be employed.

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176 Figure 4.3 Monomers that can produce hydrophilic porous polymers. 4.4.1 Potential synthetic routes One possib le novel preparation solution to covalent attachment is to brominate the meso position with N bromosuccinimide ( NBS ) on the porphyrin Porphyrin meso positions contain liable acidic protons that provide an easy exchange for bromine. T hen perform C O coupling between the porphyrin and any monomer that has an OH group such as 2 hydroxyethyl meth a crylate The brominated porphyrin c ould then react with the 2 hydroxyethyl m onomer via C O coupling reaction via a L 2 Pd (0) catalyst system. Care will need to be taken to choose the correct ligands as there would be a competing Heck reaction at the available vinyl gr oup. elimination problem can be mitigated and allow the use of ligands ideal for the Heck reaction by using a protecting group on the olefin in 2 HEMA. carbon metal complex that performs oxidative addition/insertion chemistry [3] With an unprotected olefin t he Heck reaction will ultimately lead to a bulky tri substituted vinyl group that would have a low prob ability to proceed via radical chain polymerization Figure 4.4. Theref ore to establish a more useful synthesis protection of the vinyl group on 2 HEMA must first be accomplished. This can be done by using Fp (Fp= CpFe(CO) 2 ),

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177 F igure 4. 5 Once the vinyl group is protected it can undergo a proven Pd catalyzed C O coupling synthesis as set forth by Gao et al. [4] Gao and coworkers showed in reference [4] good yield s from a wide of substrates reacting with bromina ted porphyrins where capabilities exist from large bulky sterically hindered alcohols/diols to small molecule alcohols/diols. Pd catalyzed C O coupling is depicted in Figure 4.6 The final step to obtain the porphyrin vinyl monomer for radical chain synthesis is to remove the Fp protecting group. This can be done via treatment with iodide or by warming with acetonitrile, Figure 4. 6 [3, 5] To the best of ou r knowledge t his reaction has never been perfor med and possibly offers a new synthetic route to making porphyrin substituted monomers for radical chain synthesis. This can allow novel synthesis for pendent linear, and dendrimer polymers containing porphyrin components

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178 Figure 4. 4 Heck Reaction coupling porphyrin to 2 elimination. Catalysts for Heck can be L 4 Pd, Pd(dba) 2, PdCl 2 L 2 + DIBAL, Pd(OAc) 2 + reducing agent (CO, CH 2 =CH 2 R 3 N, R 3 P) Figure 4.5 Fp (CpFe(CO) 2 ). Binds to olefins and can be used as a protecting group.

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179 Figure 4.6 Pd catalyzed C O insertion using Fp to protect the olefin 4.5 References 1. Schmidt GMJ Pure and Applied Chemistry 1971;27(4):647 678. 2. Zourob M, Mohr S, Mayes AG, Macaskill A, Perez Moral N, Fielden PR, and Goddard NJ Lab on a Chip 2006;6(2):296 301. 3. Hegedus LS. Transi tion Metals in the Synthesis of Complex Organic Molecules, 2nd ed Sausalito, CA: University Science Books, 1999. 4. Gao GY, Ruppel JV, Fields KB, Xu X, Chen Y, and Zhang XP Journal of Organic Chemistry 2008;73(13):4855 4858. 5. Pearson AJ. Iron Compounds in Organ ic Synthesis. San Diego, CA: Aca demic Press, 1994.

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ABOUT THE AUTHOR Brent Hilker was born in New Port Richey, Florida. He joined the United States Marine Corps where he served honorably as a Cryptologic Spanish Linguist for 6 years. During his time he received several meritorious masts along with medals for his character and conduc t, humanitarian service, and national defense. Brent is most proud of his humanitarian service medal fo r his work in assisting immigrants from both Cuba and Haiti while he was stationed at Guantanamo Naval Base, Cuba while attached to Lima Comp any. After his honorable service in the United States Marine Corps, Brent started his academic career first obtaining an Associate of Arts from Palm Beach Community College. He continued his educational career at the University of South Florida first ob taining a Bachelors of Science in Chemistry with scholastic honors, then completing graduate school to obtain his Doctorate in Chemistry under Dr. Julie P. Harmon focusing on polymer chemistry/polymer physics.