To create functional surfaces for soft materials, such as polyurethanes, our approach is to use a semifluorinated surface modifier as minor component to the matrix material. The surface modifier, driving by reduction in surface energy, surface-concentrates to form a functionalized surface layer at the air-polymer interface. In our previous studies, linear PTMO-based polyurethanes were used as the matrix material. These systems undergo slow surface phase separation at room temperature due to the thermodynamically immiscibility of the soft blocks. In this study, chemically crosslinked matrix was developed to provides a steric hindrance to constrain the mobility of surface modifier and to form a kinetically stable surface. The physical property and morphology of base crosslinked matrix has been characterized using DSC, UTT, DMA and AFM. The surface morphology of surface modified crosslinked matrix has been characterized using AFM, DCA and XPS.

The ultimate goal of this dissertation research is to enhance the protein resistant nature of poly(ethylene oxide) (PEO) or poly(ethylene glycol) by introduction of a siloxane linker and to subsequently prepare coatings which prevent surface-induced thrombosis. The hydrophobicity and flexibility of the siloxane tether should impart both amphiphilicity and conformational mobility to the PEO chain to further decrease protein adhesion. Because adsorption of plasma (blood) proteins initiates the clotting process, coating surfaces based on these new PEO-silanes should prevent or significantly diminish thrombosis. Thus, these coatings would be extremely useful for bloodcontacting medical devices such as stents, grafts, arteriorintravenous shunts, and biosensors. Novel amphiphilic PEO-silanes were prepared with systematic variations to several key structural features, including: siloxane tether length, PEO segment length, and PEO architecture. Thus, PEO-silanes were prepared having the general formulas: a-(EtO)3Si(CH2)2-oligodimethylsiloxanen-block-[PEO8-OCH3] (n = 0, 4, and 13; linear architecture) and a-(EtO)3Si(CH2)2-oligodimethylsiloxanen-block-[PEOm-OCH3]2 (n = 0, 4, and 13; m = 6 and 12 branched architecture). The reactive triethoxysilane [(EtO)3Si-] group serves as the crosslinking or grafting moiety. The PEO segment is distanced from the (EtO)3Si- group by an oligodimethylsiloxane tether which is both hydrophobic and exhibits a high degree of chain flexibility. Crosslinked silicone coatings and surfacegrafted coatings were prepared with amphiphilic linear PEO-silanes (a-c). Crosslinked silicone coatings were also prepared with branched PEO-silanes (1a-3a and 1b-3b). All coatings showed improved resistance to common plasma proteins compared to silicone coatings. Furthermore, protein adsorption generally decreased with siloxane tether length. For crosslinked PEO-modified silicone coating systems based on linear (a-c) and branched PEO-silanes (1a-3a and 1b-3b), longer tethers enhanced PEO reorganization to the film-water interface to enhance protein resistance. In the absence of surface reorganization for surface grafted coatings prepared with linear PEO-silanes, longer siloxane tethers better inhibited protein adsorption despite a moderate decrease in graft density (sigma) and decrease in surface hydrophilicity. This indicates that longer siloxane tethers enhance the configurational mobility of the PEO segments to better repel proteins.

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on Feb. 9, 2010. Major professor: Dr. Robert Crockett. "Presented to the faculty of California Polytechnic State University, San Luis Obispo, California." "In partial fulfillment of the requirements for the degree [of] Master of Science in Engineering." "November 2009." Includes bibliographical references (p. 47-52).

Thesis (Ph.D)--University of Tulsa, 1987. / Bibliography: leaves 99-104.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Kippelen Bernard; Committee Member: Brand Oliver; Committee Member: Bredas Jean-Luc; Committee Member: Dupuis Russell D.; Committee Member: Smith Glenn S.. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Dr. William J. Koros; Committee Member: Dr. Amyn Teja; Committee Member: Dr. Christopher W. Jones; Committee Member: Dr. Haskell W. Beckham; Committee Member: Dr. Stephen J. Miller. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph.D.) -- McMaster University, 2001. / Includes bibliographical references. Also available via World Wide Web.

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