Synthesis and characterisation of water-soluble poly(ethylene glycol) modified polymethacrylates with the ability to crosslink†

Hydrogels have become increasingly important in the biomedical field. The aim of this study was to develop amphiphilic poly(ethylene glycol) grafted polymethacrylates with curable side groups. The water-soluble polymers were synthesised by free-radical copolymerisation of methyl methacrylate, α-methyl-ω-methacroyl-poly(ethylene glycol) and 2-hydroxyethyl methacrylate (HEMA). The methacrylate containing hydrogel precursors were obtained by reacting the free hydroxyl groups of HEMA in the polymer with methacrylic anhydride in the presence of catalyst. γ-Irradiation has been used as an elegant method for crosslinking and simultaneous sterilisation. The influence of the irradiation dose (5, 15, 25 kGy) on the polymers was examined by the determination of the gel and sol fraction. In an aqueous environment these materials behave as hydrogels with more swelling at lower temperatures. Since the coatings can be applied in mild conditions, eg water, these materials are looking very promising as thin film coatings for biomedical applications.