Title

Surface Modifications of Polymeric Materials For Bio Applications

Author

Woo-Sung Bae

Date of Award

2006

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Polymers and High Performance Materials

First Advisor

Marek W. Urban

Advisor Department

Polymers and High Performance Materials

Abstract

This dissertation consists of two parts; (1) emulsion polymerization of sugar-stabilized colloidal particles that leads to formation of competitive adsorption of proteins and (2) microwave plasma surface modification of polymeric surfaces and subsequent surface polymerization reaction. Specific surfactants such as dodecyl-β-D-maltoside (DDM) nonionic and sodium dioctylsulfosuccinate (SDOSS) ionic surfactants for emulsion polymerization are employed for stabilizing agents. These studies show that when DDM is utilized for the synthesis and stabilizing agents of poly [methyl methacrylate-co-(n-butyl acrylate)] (p-MMA/nBA) colloidal particles, upon particle coalescence DDM stratifies near the film-air (F-A) interface. Using attenuated total reflectance Fourier transform IR (ATR FT-IR) spectroscopy and internal reflection IR imaging (IRIRI), comparative adsorption studies on p-MMA/nBA surfaces exposed to globulin (Glo), fibrinogen (Fib), and bovine serum albumin (BSA) reveal that the presence of DDM selectively inhibits Glo and Fib adsorption, but does not affect BSA. The presence of DDM also enhances the rate of mobility of SDOSS resulting from interactions between DDM and SDOSS moieties, and the surface morphologies change as a result of concentration variations of DDM in the colloidal dispersions. Furthermore, the bio-recognition properties of such p-MMA/nBA films containing DDM are investigated regarding not only the binding properties of the colloidal dispersion contained DDM with concanavalin A (Con A) but also interactions between Con A and α-glucose moiety of DDM at the F-A interfaces of coalesced p-MMA/nBA films. Poly(dimethylsiloxane) (PDMS) surfaces are functionalized using microwave plasma reactions with several monomers. When imidazole and its derivatives such as 2-methylimidazole and 2-ethylimidazole are used, the mechanism of reactions for each monomer is dependent not only upon the reaction time, but also molecular structure of monomers. For methyl and ethyl substituted imidazoles, more stable radical species are generated in the high-energy plasma environments. Using microwave plasma reactions we created highly reactive surface functional groups utilized for further reactions, thus resulting in the attachment of antimicrobial drugs such as chloramphenicol and amoxicillin. By using maleic anhydride monomers, PDMS surfaces were modified with anhydride and carboxylic acids in a way of patterning that is utilized for attaching initiators on the PDMS surfaces to conduct surface initiated polymerization reactions. N-isopropylacrylamide (NIPAAM), N ,N '-dimethylacrylamide (DMA), p -styrenesulfonate (PSS), and (ar -vinylbenzyl)trimethylammonium chloride (VBTAC) are employed to fabricate grafted polymers on the initiator attached PDMS surfaces using conventional free radical (CFRP) and reversible addition-fragmentation chain transfer (RAFT) polymerizations. Furthermore, poly(VBTAC) tethered PDMS surfaces exposed to p-PSS and p-VBTAC solutions allowed us to create ionic self-assembly multilayers on the PDMS surface.