Radiation‐grafted polymers for biomaterial applications. II. The morphology and structure of 2‐hydroxyethyl methacrylate and ethyl methacrylate homopolymer grafts

The 2‐hydroxyethyl methacrylate (HEMA)/ethyl methacrylate (EMA) graft copolymer system has been found to be a useful model for investigating blood/polymer interactions. Studies of the structure of both HEMA and EMA radiation‐grafted regions were conducted using extraction methods and transmission electron microscopy of selectively stained HEMA grafts. The effect of the extraction procedure on the surface topography of HEMA‐ or EMA‐grafted films was studied by means of scanning electron microscopy. The existence of internal cells in the bulk of the HEMA network was demonstrated, and their osmotic nature was investigated. As grafting proceeds, the HEMA network becomes increasingly porous. The extraction studies carried out on EMA grafted showed that with this system an increasingly dense structure is obtained as grafting proceeds.