PULSED PLASMA DEPOSITION of SURFACE FUNCTIONAL THIN FILMS a Thesis Presented to the Graduate Faculty of the University of Akron
Total Page：16
File Type：pdf, Size：1020Kb
PULSED PLASMA DEPOSITION OF SURFACE FUNCTIONAL THIN FILMS A Thesis Presented to The Graduate Faculty of The University of Akron In Partial Fulfillment of the Requirements for the Degree Master of Science Nickolas R. Kaiser May 2017 PULSED PLASMA DEPOSITION OF SURFACE FUNCTIONAL THIN FILMS Nickolas R. Kaiser Thesis Approved: Accepted: ______________________________ ______________________________ Advisor Dean of the College Dr. Ali Dhinojwala Dr. Eric J. Amis ______________________________ ______________________________ Faculty Reader Interim Dean of the Graduate School Dr. Coleen Pugh Dr. Chand Midha ______________________________ ______________________________ Department Chair or School Director Date Dr. Coleen Pugh ii ABSTRACT Radio Frequency (RF) Plasma deposition has proven to be an unusually convenient and universal surface-modification and coating technology for grafting thin film for applications in which solution chemistry is difficult or entirely impossible, or adhesion to a low energy substrate surface is desired1. The one-step gas to solid-phase nature of the process eliminates liquid solvents, which are otherwise required for spin coating, electro- deposition, and other traditional coating processes. The technique uses excited plasma in a volume of monomer vapor, forming reactive energetic species (radicals and ions). The recombination of surface-bound free radicals and ions with airborne radicals and oppositely charged ions creates strong substrate-independent covalent attachment at the interface2. Pulsing of the incident electrical energy significantly reduces the total energy absorbed by the targeted vapor, subsequently minimizing bond scission and energetic structure rearrangement to retain useful functional groups. In this work, Terpyridine was tethered to various substrates and complexed with iron, forming a film that may readily complex with other Terpyridine-coated substrates to form an adhesive bond. Thin films of reactive anhydride were first deposited by maleic anhydride vapor in a pulsed plasma process. The highly reactive anhydride group was retained in the plasma with low input power, short duty cycle on-time, and long duty cycle off-times3. A primary amine-functional Terpyridine was tethered to the anhydride film via aminolysis and heated to form a stable maleimide linkage. iii TABLE OF CONTENTS List of Figures ....................................................................................................... vii List of Tables ......................................................................................................... ix CHAPTER I. FUNDAMENTALS OF PLASMA Introduction ......................................................................................................1 Plasma state ......................................................................................................1 Fundamentals of Gas and Molecular collisions ...............................................3 Classification of plasmas .................................................................................6 Hot vs. Cold plasma ....................................................................................7 Hot plasmas (near-equilibrium plasmas) .........................................................8 Non-equilibrium (cold plasmas) ......................................................................9 Low-pressure, non-equilibrium plasmas ...................................................12 Atmospheric pressure, non-equilibrium plasmas ......................................13 Modulated plasmas (pulsed plasmas) .............................................................14 II. APPLICATIONS OF PLASMA TECHNOLOGY Applications of non-equilibrium plasmas ......................................................16 Plasma Sputtering ..........................................................................................18 Plasma Surface Modification .........................................................................19 Plasma Etching...............................................................................................22 Plasma Sterilization .......................................................................................23 Plasma Polymer Deposition ...........................................................................24 iv III. DEPOSITION AND DERIVITATION OF FUNCTIONAL FILMS Maleic Anhydride Chemistry .........................................................................28 Maleic Anhydride Deposition ........................................................................31 Maleic Anhydride Derivatization ..................................................................33 IV. DERIVITIZATION AND ADHESION Introduction ....................................................................................................34 Reversible Adhesion ......................................................................................34 Gecko Tape ...............................................................................................35 Click Chemistry ........................................................................................36 Terpyridine ................................................................................................37 V. EXPERIMENTAL METHODS Introduction ....................................................................................................39 Equipment and Apparatus ..............................................................................40 Materials ........................................................................................................43 Methods..........................................................................................................45 VI. RESULTS AND DISCUSSION Maleic Anhydride Plasma Polymerization ...................................................48 Maleic Anhydride Plasma Polymer Derivitization Reactions .......................50 Diethylene Triamine .................................................................................50 Aminopropyltriethoxysilane .....................................................................52 Rubidium-complexed Aminophenyl terpyridine ......................................54 Pentylamine Terpyridine ...........................................................................58 v VII. CONCLUSION AND FUTURE WORK ......................................................63 REFERENCES ......................................................................................................65 vi LIST OF FIGURES Figure Page 1.1 Range of plasmas ...............................................................................................2 1.2 Common States of Matter ..................................................................................3 1.3 Debye Sphere Illustration .................................................................................4 1.4 Schematic of Plasma Stars .................................................................................7 1.5 Plasma Reactor Schematic ...............................................................................10 1.6 Atmospheric Plasma Reactor Schematic .........................................................14 2.1 Schematic of plasma chamber .........................................................................19 2.2 Pulsed Plasma Reactor Electrical System Schematic ......................................27 3.1 Molecular Structure of Maleic Anhydride .......................................................28 3.2 Examples of Cycloaddition with Maleic Anhydride .......................................30 3.3 Molecular Structure of poly(Maleic Anhydride) .............................................31 3.4 Schematic for the Aminolysis of Maleic Anhydride .......................................33 4.1Schematic of Gecko Foot Pad Adhesion ..........................................................36 4.2 Mechanism of A Click Reaction ......................................................................37 4.3 Aminolysis and Amidization of Maleic Anhydride with Aminoterpyridine ...38 5.1 Photograph of Pulsed Plasma Reactor Used in Studies ...................................41 5.2 Molecular Structure of Aminophenyl Terpyridine ..........................................43 5.3 Synthesis Schematic of Aminopentyl Terpyridine ..........................................44 5.4 H1-NMR Spectrum of the Aminopentyl Terpyridine Product ........................45 6.1 Grazing angle FT-IR spectrum of Maleic Anhydride film ..............................49 6.2 XPS Elemental analysis of MA film ................................................................50 vii 6.3 Grazing angle FTIR Spec of Maleic Anhydride/Diethylene Triamine Film ...51 6.4 Magnified FTIR Spectrum of Maleic Anhydride/Diethylene Triamine Film .51 6.5 frazing angle FTIR Spectrum of Maleic Anhydride/Aminosilane Film ..........52 6.6 Magnified FTIR Spectrum of Maleic Anhydride/ Aminosilane Film .............53 6.7 XPS Elemental analysis of Maleic Anhydride/ Aminosilane film ..................54 6.8 FTIR Spectrum of Maleic Anhydride/Aminophenyl Terpyridine ...................55 6.9 XPS analysis of Maleic Anhydride/ Aminophenyl Terpyridine film ..............56 6.10 Magnified XPS Peak of Nitrogen ..................................................................57 6.11 Magnified XPS Peak of Rubidium ................................................................57 6.12 Grazing angle FTIR of Maleic Anhydride/Aminopentyl Terpyridine ...........59 6.13 Magnified FTIR