Surface modification of natural rubber latex films via grafting of poly(ethylene glycol) for reduction in protein adsorption and platelet adhesion

Natural rubber (NR) latex films with surface grafted poly(ethylene glycol) (PEG) chains were prepared by UV-induced graft copolymerization of methoxy poly(ethylene glycol) monomethacrylate (PEGMA) onto the plasma-pretreated NR latex films. PEGMA macromononers of different molecular weights were used. The UV-induced graft copolymerization of PEGMA onto the plasma-pretreated NR latex films was also explored with PEGMA of different macromonomer concentrations and with different UV graft copolymerization time. The surface microstructures and compositions of the PEG-modified NR latex films were characterized by contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) measurements. In general, higher macromonomer concentration and longer UV graft copolymerization time led to a higher graft yield. Water contact angle measurements revealed that the hydrophilicity of the NR latex film surface was greatly enhanced by the grafting of the PEG chains. The NR surface with a high density of grafted PEG was very effective in reducing protein adsorption and platelet adhesion. A lower graft concentration of the high-molecular-weight PEG was more effective than a high graft concentration of the low-molecular-weight PEG in reducing protein adsorption and platelet adhesion. (C) 2001 Kluwer Academic Publishers.