The Hydrophilic Modification Of Polyurethane Surface

It was well known that the biocompatibility of polyurethane could be improved by grafting hydrophilic molecules to the surface, as the hydrophilic surface could reduce the non-specific protein adsorption. In this research, various hydrophilic molecules were grafted to the polyurethane by different method. The hydrophilicity and protein resistant property of resulting surfaces were studied."Graft to" method was employed to graft macromolecules to the surface in the first part of this research. Polyurethane was functionalized by Diphenyl methane-4,4'-diisocyanate (MDI) , and following by conjugate Tris to magnify the amount of function group. Polyethylene glycol (PEG) was grafted to the surface, which had been modified by MDI through Tris. The reaction conditions were optimized by studying the water contact angle and protein adsorption of the modified surface. Although the hydrophilicity of modified surface was not influence by the different molecular weight and end groups of short chain PEG, the protein adsorption of different modified surface changed significantly. Due to the steric hindrance, grafting PEG through Tris didn't improve the protein resistant property as we expected.The "graft from" method was applied to graft macromolecules to the polyurethane in the second part of this research. After functionalized by MDI, polyurethane was modified by various monomers including acrylic acid, acrylamide and 2-hydroxyethyl methacrylate. Following by radical polymerization and UV initiation, respectively, different hydrophilic surfaces were formed. The hydrophilicity and protein resistant property of resulting surfaces were discussed.