SURFACE MODIFICATION OF POLYURETHANE BY PLASMA-INDUCED GRAFT-POLYMERIZATION OF POLY(ETHYLENE GLYCOL) METHACRYLATE

A new approach, plasma-induced graft polymerization of poly(ethylene g lycol) methacrylate (PEGMA), was used to introduce PEG graft chains wi th hydroxyl end groups onto a polyurethane (Tecoflex) surface. After a rgon plasma treatment and subsequent exposure to air, graft polymeriza tion onto Tecoflex films was allowed to proceed in deaerated aqueous s olutions of PEGMA at 60 degrees C. The virgin, plasma-treated, and gra fted films were characterized comparatively by means of attenuated tot al reflection infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, measurement of contact angle, and protein ad sorption. The Tecoflex film undergoes etching during argon plasma trea tment, surface oxidation when exposed to air after plasma treatment, a nd surface restructuring in response to environment upon storage in ai r. The plasma-induced graft polymerization of PEGMA proved to be succe ssful in introducing PEG graft chains with reactive hydroxyl end group s onto the surface. Grafted films with different surface grafting dens ity of PEG were prepared. Grafted films with higher PEG content exhibi t higher hydrophilicity, smoother topography, and lower fibrinogen ads orption. The hydroxyl end groups built onto the surface offer further possibilities of improving its biocompatibility by immobilizing bioact ive molecules. (C) 1996 John Wiley & Sons, Inc.