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THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
GEORGIA INSTITUTE OF TECHNOLOGY
Under the provisions of the regulations for the degree
DOCTOR OF PHILOSOPHY
onTHURSDAY May 31, 2018
11:00 AM
in MoSE 3201A
will be held the
DISSERTATION PROPOSAL DEFENSE
for
Anise Grant
"Biopolymer and Synthetic Polymer Nanocomposite Reinforcement via Interfacial Assembly"
Committee Members:
Dr. Vladimir Tsukruk, Advisor, MSE
Dr. Rajesh Naik, AFRL
Dr. Zhiqun Lin, MSE
Dr. Valeria Milam, MSE
Dr. Meisha Shofner, MSE
Abstract:
Protein biopolymer composites bring together the tunability and flexibility of protein matrices and functionality of filler components. We fabricate biopolymer and synthetic polymer nanocomposites then explore the role of interfacial assembly in composite reinforcement. To do this, we identify ways to control polymer assembly via pH, temperature, hydrophobicity, and salt addition. Specifically, we discuss the assembly of silk fibroin (SF), SF-like proteins, and synthetic copolymers at inorganic interphases; the implications of assembly on mechanical performance; and how this relates to previous findings with SF. We begin our study with a focus on the well-studied silk fibroin then synthetic copolymers for simpler structures with controlled composition and configuration, and finally the silk-like but little researched Humboldt squid sucker ring teeth protein suckerin-12.
Experimentally, we identify material processing conditions that induce biopolymer and synthetic polymer interfacial assembly, such as temperature, shear force, hydropathy, and pH. Interfacial forces and polymer assembly are monitored by high resolution attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), scanning probe microscopy (SPM), and a range of other surface spectroscopic techniques. Then, we identify aggregation and elongation behaviors characteristic after using specific processing procedures. We compare experimental and simulation data to hypothesize underlying mechanisms and the timescale of their effects. Simulations are used to probe the interfacial forces contributing to the conformational behavior and corroborate FTIR and atomic force microscopy (AFM) observations. The simulations will be used to calculate the magnitude of interfacial forces and map individual molecular motion overtime. And, finally, we correlate interfacial assembly with mechanical performance and apply these findings to drive material design. Mechanical performance will be evaluated at the macro and nanoscales using quantitative nanomechanical mapping, force distance spectroscopy, and buckling tests.
