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Chemical modification of solid surfaces and interfaces and template-assisted fabrication of surface nanostructures
Chapter One describes the use of supercritical carbon dioxide (scCO 2) as an agent for the conduction of silane chemistry at the buried interfaces between silicon wafers and spin-cast polymer thin films. Above the critical point of CO2, organosilanes react with surface silanols at the SiO2/polystyrene interface to form a monolayer quantitatively. The ability to do chemistry selectively at weak interfaces offers the potential to rehabilitate coatings and composites. Chapter Two describes the chemical surface modification of nylon 6/6. Several methods were developed for introducing reactive functional groups to nylon 6/6 surfaces using amide-selective reagents at the solid polymer - solution interface. Hydrolysis of nylon 6/6 yields a surface mixture of amine and carboxylic acid groups. Different alkylating agents, including 2-bromoethylamine, allyl bromide, 1,4-dibromobutane and 4-(trifluoromethyl)benzyl bromide were studied. Reaction of the activated amides with 3-glycidoxypropyltriethoxysilane offers a pathway for generating surfaces with silica-like reactivity. The enrichment of nylon 6/6 with amine functional groups greatly enhances the electroless deposition of gold. Equally important is the ability to generate surface structures at the nanometer scale in a controlled fashion. Chapter Three and Chapter Four describe the generation of silicon dioxide (SiO2) nanostructures on silicon wafers using both an organosilane monolayer and a block copolymer thin film as templates, respectively. The resulting surfaces exhibit controlled variation of roughness at the nanometer scale. Contact angle analysis indicates that the effect of nanoscale roughness on wettability is important. Nanoporous films generated from asymmetric block copolymers of styrene and methyl methacrylate (P(S-b-MMA)) were used as scaffolds to define an ordered array of nanoscopic reaction vessels. Nanoscopic posts of silicon oxide on silicon wafers were produced within the pores defined by the crosslinked matrix. Reactive ion etching selectively removed the organic matrix, leaving free-standing silicon dioxide posts on silicon wafers. Chapter Five describes the examination of the adsorption behavior of different proteins (albumin, lysozyme and collagen) toward surfaces that exhibit nanoscale features. (Abstract shortened by UMI.)
Jia, Xinqiao, "Chemical modification of solid surfaces and interfaces and template-assisted fabrication of surface nanostructures" (2002). Doctoral Dissertations Available from Proquest. AAI3068568.