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I. Composite Polymer Coatings Prepared in Supercritical Carbon Dioxide

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I. Composite Polymer Coatings Prepared in Supercritical Carbon Dioxide University of Massachusetts Amherst ScholarWorks@UMass Amherst Doctoral Dissertations 1896 - February 2014 1-1-2006 I. Composite polymer coatings prepared in supercritical carbon dioxide. II. Chemical modification of atomic force microscope probes. III. Liquid mobility on surfaces with patterned chemistry and topography. Kevin A. Wier University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/dissertations_1 Recommended Citation Wier, Kevin A., "I. Composite polymer coatings prepared in supercritical carbon dioxide. II. Chemical modification of atomic force microscope probes. III. Liquid mobility on surfaces with patterned chemistry and topography." (2006). Doctoral Dissertations 1896 - February 2014. 1088. https://scholarworks.umass.edu/dissertations_1/1088 This Open Access Dissertation is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Doctoral Dissertations 1896 - February 2014 by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. University of Massachusetts Amherst I B R A R Y 1 : 5 ! ) I This is an authorized facsimile, made from the microfilm master copy of the original dissertation or master thesis published by UMI. The bibliographic information for this thesis is contained in UMFs Dissertation Abstracts database, the only central source for accessing almost every doctoral dissertation accepted in North America since 1861. ® Dissertation UMI Services From:Pro(jsuest COMPANY 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Michigan 48106-1346 USA 800.521.0600 734.761.4700 web www.il.proquest.com Printed in 2006 by digital xerographic process on acid-free paper I. COMPOSITE POLYMER COATINGS PREPARED IN SUPERCRITICAL CARBON DIOXIDE II. CHEMICAL MODIFICATION OF ATOMIC FORCE MICROSCOPE PROBES III. LIQUID MOBILITY ON SURFACES WITH PATTERNED CHEMISTRY AND TOPOGRAPHY A Dissertation Presented by KEVIN A. WIER Submitted to the Graduate School of the University of Massachusetts Amherst in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2006 Polymer Science and Engineering UMI Number: 3215774 UMI UMI Microform 3215774 Copyright 2006 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 © Copyright by Kevin A. Wier 2006 All Rights Reserved I. COMPOSITE POLYMER COATINGS PREPARED IN SUPERCRITICAL CARBON DIOXIDE II. CHEMICAL MODIFICATION OF ATOMIC FORCE MICROSCOPE PROBES III. LIQUID MOBILITY ON SURFACES WITH PATTERNED CHEMISTRY AND TOPOGRAPHY A Dissertation Presented by KEVIN A. WIER Approved as to style and content by: Thomas J. McCarthy, Chair Alfred J. Crosby, Member Anthony D. Dinsmore, Member Shaw Ling Hsu, Department Head Polymer Science and Engineering I. COMPOSITE POLYMER COATINGS PREPARED IN SUPERCRITICAL CARBON DIOXIDE II. CHEMICAL MODIFICATION OF ATOMIC FORCE MICROSCOPE PROBES III. LIQUID MOBILITY ON SURFACES WITH PATTERNED CHEMISTRY AND TOPOGRAPHY A Dissertation Presented by KEVIN A. WIER Approved as to style and content by: Thomas J. McCarthy, Chair Anthony D. Dinsmore, Member Shaw Ling Hsu, Department Head Polymer Science and Engineering ACKNOWLEDGMENTS My years spent in graduate school would not have been as successful or enjoyable without the support and encouragement of many friends and colleagues. I would like to thank my advisor Professor Tom McCarthy for his guidance and direction during my graduate career. His enthusiasm and creative perspectives about science were a great example of how interesting and exciting research could be. Professor Al Crosby not only made helpful remarks about my research as a member of my committee, but was also a valuable resource of information during my job search and about graduate school in general. I also thank my other committee member Professor Tony Dinsmore for his comments and critiques of my research. The most rewarding part of graduate school for me was the wonderful people I met. I want to thank the past and present members of the McCarthy group for making it enjoyable to come to lab each day and for all their help and camaraderie throughout the years. Thanks to Jack, Jeff, Chris, Xinqiao, Margarita, Wei, Ebru, Taehyung, Zhixiang, Sung In, like, Lichao, Yufeng, Scott, and especially Misha, Jung Ah, and Jay. I was also blessed with wonderful classmates and housemates who made my time spent in Amherst particularly pleasant. There is more to life than just science and I want to thank Bryan, Greg, Lachelle, Drew, Matt, Sian, and Brad for providing much needed respites from the stresses of graduate school. I am especially grateful for the love and support of my parents. Bob and Mary, and sisters, Kristin and Sherrie. Their faith and unwavering encouragement helped me throughout this life-changing journey. iv ABSTRACT I. COMPOSITE POLYMER COATINGS PREPARED IN SUPERCRITICAL CARBON DIOXIDE II. CHEMICAL MODIFICATION OF ATOMIC FORCE MICROSCOPE PROBES III. LIQUID MOBILITY ON SURFACES WITH PATTERNED CHEMISTRY AND TOPOGRAPHY MAY 2006 KEVIN A. WIER, B.S., MICHIGAN TECHNOLOGICAL UNIVERSITY Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Thomas J. McCarthy The initial part of this dissertation describes the preparation of the first reported poly(p-xylylene) polymer/polymer composites. Poly(/?-xylylene) (PPXN) and its derivatives, known collectively as parylenes, are solvent resistant and blends or composites cannot be easily made by conventional methods. Supercritical carbon dioxide was used as both a plasticizer and solvent to infuse and polymerize a variety of vinyl monomers inside the parylene films. Infrared spectroscopy, wide angle X-ray diffraction, and thermal gravimetric analysis were used to characterize the composites. Multilayer coatings of PPXN and other polymer films were prepared and selectively modified with metal nanoparticles. The second part details the modification of atomic force microscope (AFM) probes using a variety of monochlorosilanes to improve the chemical sensitivity of AFM. X-ray photoelectron spectroscopy revealed that the silane reaction was successful. Adhesion force measurements between the modified probes and similarly modified silicon wafers were performed, but showed only a slight variance between the V different tip chemistries. Surfaces with patterned chemistry were prepared and examined with the modified probes using tapping mode AFM. The contrast in the phase images was dependent on the tip chemistry. The ability to confine and direct the motion of hquid droplets on a surface using only gravity and differences in surface chemistry is discussed in the first chapter of Part in. A hydrophobic alkylsilane surface with low contact angle hysteresis was patterned with lines of a more hydrophobic fluoroalkyl silane. Liquid droplets moved easily on the low hysteresis matrix, but pinned at the more hydrophobic lines. A variety of patterns were used to demonstrate that a decrease in the hysteresis reduces the force needed to induce drop motion and also lowers the barriers that are needed to confine the droplets. Condensation on a variety of ultrahydrophobic surfaces was examined in the second chapter of Part III. Optical microscopy showed that water condensed between the hydrophobic surface features before being expelled to the top. The condensed liquid pinned the contact line of a macroscopic droplet and dynamic contact angle measurements revealed an increase in hysteresis which corresponded to a decrease in liquid mobility. vi 81 TABLE OF CONTENTS Page ACKNOWLEDGMENTS iv ABSTRACT v LIST OF TABLES xii LIST OF FIGURES xiv CHAPTER 1 . POLY(P-XYLYLENE) COMPOSITE COATINGS PREPARED IN SUPERCRITICAL CARBON DIOXIDE 1 1.1 Introduction 1 1 .2 Background 3 1.2.1 Supercritical Carbon Dioxide 3 1.2.2 Poly(/?-xylylene) 6 1.2.3 Chemical Modification of Poly(p-xylylene) 10 1.3 Experimental 13 1.3.1 Materials 13 1.3.2 Experimental Procedures 14 1.3.2.1 Modification of Silicon Wafers 14 1.3.2.2 Chemical Vapor Deposition of Poly(/;-xylyene) 15 1.3.2.3 Absorption Kinetics 15 1.3.2.4 Polymer Composite Synthesis 15 1.3.2.5 Metal Composite Synthesis 16 1.3.2.6 PPXN/PECA Multilayer Coatings 17 1.3.3 Characterization 18 1.4 Results and Discussion 18 1 .4. 1 Vapor Deposition of Poly(p-xylylene) 1 1.4.2 Phase Behavior and Absorption Kinetics 20 1 .4.3 PPXN Polymer Composites 2 1 .4.4 Poly(chloro-/?-xylylene) Composites 32 1 .4.5 Polymer Composites on Silicon Wafers 33 Vll 1.4.6 Composite Characterization 34 1.4.6.1 Thermal Properties 34 1 .4.6.2 X-ray Diffraction 35 1.4.7 Parylene/Metal Composites 37 1.4.8 PPXN/PECA Multilayer Templates 40 1.5 Conclusions 41 1.6 References 43 2. MODIFICATION OF ATOMIC FORCE MICROSCOPE PROBES FOR IMPROVED SURFACE CHEMICAL IDENTIFICATION 51 2.1 Introduction 51 2.2 Background 52 2.2.1 Atomic Force Microscope 52 2.2. 1 . 1 Contact Mode AFM 52 2.2. 1 .2 Tapping Mode AFM 54 2.2.2 AFM Probe Surface Chemistry 55 2.2.3 AFM Probe Surface Modification 56 2.2.4 Surface Chemical Analysis Using AFM 58 2.2.4. 1 Force Curves 58 2.2.4.2 Lateral/Friction Force Images 60 2.2.4.3 Tapping Mode Phase Images 61 2.3 Experimental 63 2.3.1 Materials 63 2.3.2 Experimental Procedures 64 2.3.2.1 Silane Modification 64 2.3.2.2 Silicon Dioxide Growth and Modification 64 2.3.2.3 Microcontact Printing 65 2.3.3 Characterization 66 2.3.3.1 Chemical Force Microscopy 67 2.3.3.2 X-ray Photoelectron Spectroscopy 67 2.4 Results and Discussion 70 Vlll 2.4.1 Silane Modification of Probes and Surfaces 70 2.4.2 Adhesion Force Measurements 74 2.4.3 Tris(TMS)/Si02/Silane Surfaces 78 2.4.3.1 Silicon Dioxide Growth and Modification 78 2.4.3.2 Phase Images 83 2.4.4 Microcontact Printed Thiol Surfaces 85 2.4.4.1 Preparation 85 2.4.4.2 AFM Characterization 90 2.5 Conclusions 92 2.6 References 94 3.
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