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Ultra-Robust Graphene Based Bio-Nanocomposites and Their Electronic Applications

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Ultra-Robust Graphene Based Bio-Nanocomposites and Their Electronic Applications Ultra-Robust Graphene Based Bio-Nanocomposites and Their Electronic Applications A Dissertation Presented to The Academic Faculty by Kesong Hu In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Materials Science and Engineering Georgia Institute of Technology May 2016 Copyright © 2016 by Kesong Hu Ultra-Robust Graphene Based Bio-Nanocomposites and Their Electronic Applications Approved by: Dr. Vladimir V. Tsukruk, Advisor Dr. Zhiqun Lin School of Materials Science and School of Materials Science and Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Kyriaki Kalaitzidou Dr. Eric Vogel Woodruff School of Mechanical School of Materials Science and Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Satish Kumar School of Materials Science and Engineering Georgia Institute of Technology Date Approved: December 16th, 2015 Dedicated to my family ACKNOWLEDGEMENTS I appreciate the financial support from the Air Force Office of Scientific Research for the study on the bioinspired nanocomposites. I would like to take this opportunity to express my appreciation to my academic advisor, Dr. Vladimir V. Tsukruk, who has been guiding and inspiring me for the last four and half years, and made significant impact not only in my research career but also in my entire life. I also want to thank Dr. Kyriaki Kalaitzidou, Dr. Satish Kumar, Dr. Zhiqun Lin, and Dr. Eric Vogel, who devoted their precious time to serve on my PhD proposal and defense committees. Special thanks to Dr. Satish Kumar, Dr. Eric Vogel, Dr. David Kaplan, and Dr. Luzinov, who provided tremendous support to my ongoing research activity by sharing their expertise, insights, and instruments. Dr. Maneesh K. Gupta and Dr. Dhaval D. Kulkarni were senior members in our group and mentored me to initiate the lab work in this study. All SEMA members have contributed to the excellent working environment and the perfect collaboration chemistry in the entire lab. I would thank everybody for sharing their passion, intelligence, talent, and patience to help me arrive at this stage. Specifically, Dr. Yi Yin, Dr. Chunhong Ye, Dr. Ikjun Choi, Rui Xiong, Lorenzo Tolentino, Anise Grant, Ruilong Ma, Paul Zackowski, and Michael Russel have provided significant collaboration or assistance at different stages of my research for multiple meaningful projects, which stand no chance to be as impactful as they are without their help. Special thanks also go to Dr. Wenzhuo Wu from Prof. Zhong Lin Wang’s group for offering great opportunities to expand the application of graphene oxide- silk fibroin system to triboelectric nanogenerators. Lastly, I appreciate the unconditional support from my parents and my wife, Shuai Xiang. They founded the basis of my pursuit of my gem of the academic crown – Doctor of Philosophy. The love and everything they have granted me can never be paid back equally, but I will try for my entire life. TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................ iii LIST OF TABLES ......................................................................................................... viii LIST OF FIGURES ......................................................................................................... ix SUMMARY .................................................................................................................. xviii Chapter 1 Introduction to polymer nanocomposites ..................................................1 1.1 Background ......................................................................................................................... 1 1.1.1 Choice of polymeric matrices .................................................................................. 1 1.1.2 Reinforcing components .......................................................................................... 4 1.1.3 Graphene-based nanocomposites ............................................................................. 6 1.1.4 Graphene and graphene derivatives as prospective filler nanomaterials ................. 9 1.1.5 Interfacial interactions and polymer matrices ........................................................ 13 1.2 Theoretical grounds for the selection of nanofillers ...................................................... 16 1.2.1 Models for particulate nanocomposites ................................................................. 17 1.2.2 Models for nanocomposites with anisotropic fillers .............................................. 18 1.2.3 Interphases in nanocomposites ............................................................................... 21 1.3 Processing of the graphene-polymer nanocomposites ................................................... 22 1.3.1 Examples of solution-based processing ................................................................. 23 1.3.2 Examples of melt-based processing ....................................................................... 26 1.3.3 LbL assembly of graphene components ................................................................. 31 1.4 Mechanical properties of graphene–polymer nanocomposites .................................... 35 1.4.1 Graphene papers ..................................................................................................... 38 1.4.2 Graphene-polymer nanocomposites via weak interfacial interactions ................... 42 1.4.3 Incorporation of graphene fillers into nanocomposites .......................................... 46 1.4.4 Hydrogels reinforced by graphene derivatives ...................................................... 48 1.5 Other functional properties and applications ................................................................ 51 1.5.1 Graphene-polymer nanocomposites for sensing applications ................................ 52 1.5.2 Graphene-polymer nanocomposites as gas barriers ............................................... 53 1.5.3 Graphene-polymer nanocomposites for photovoltaic applications ........................ 54 1.5.4 Graphene-polymer nanocomposites with high thermal conductivity .................... 56 1.5.5 Graphene-polymer nanocomposites with electrical conductivity .......................... 57 1.6 Status and Issues ............................................................................................................... 61 Chapter 2 Research Goals, Objectives, and Overview .............................................66 iv 2.1 Goals .................................................................................................................................... 66 2.2 Objectives ........................................................................................................................... 68 2.3 Organization and composition of dissertation ................................................................. 71 Chapter 3 Experimental Methods ..............................................................................76 3.1 Materials ............................................................................................................................ 76 3.1.1 Synthesis of graphite oxide .................................................................................... 76 3.1.2 Silk fibroin processing ........................................................................................... 76 3.1.3 Cellulose nanocrystal fabrication and modification ............................................... 77 3.2 Sample fabrication............................................................................................................ 78 3.2.1 Spin-assisted layer-by-layer (SA-LbL) .................................................................. 78 3.2.2 Dynamic spin-assisted layer-by-layer (dSA-LbL) ................................................. 78 3.2.3 Vaccum-assisted filtration (VAF) .......................................................................... 79 3.2.4 Metal deposition ..................................................................................................... 80 3.2.5 Chemical reduction of graphene oxide .................................................................. 80 3.2.6 Photolithography .................................................................................................... 81 3.3 Characterizations ............................................................................................................. 81 3.3.1 Ellipsometry ........................................................................................................... 81 3.3.2 Atomic force microscopy (AFM) .......................................................................... 81 3.3.3 Scanning electron microscopy (SEM) ................................................................... 82 3.3.4 Transmission electron microscopy (TEM)............................................................. 82 3.3.5 X-ray diffraction (XRD) ........................................................................................ 82 3.3.6 X-ray photoelectron spectroscopy (XPS) .............................................................. 82 3.3.7 Raman Spectroscopy .............................................................................................. 83 3.3.8 Fourier transform infrared spectroscopy (FTIR).................................................... 83 3.3.9 UV-Vis spectroscopy ............................................................................................
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