Swelling behavior of poly (2-hydroxyethyl methacrylate) copolymer gels

Hydrogels based on 2-hydroxyethyl methacrylate/dimethyl-aminoethyl methacrylate copolymers were prepared by gamma radiation-inducedco-polymerization at low temperature (−78◦C). The swelling behavior of hydrogels was studied by immersion of the polymer discs in buffered solutions at pH from 2 to 10. The hydration process was followed gravimetrically by measuring the water uptake of the discs as a function of time. The results obtained have shown that the swelling behavior is reversible and depends on the polymer nature. Moreover, polymeric discs exhibited a good stability after repeating cycles of hydration in different buffer solutions. Scanning electron microscopy analysis reveals that hydrogel porosity can be controlled.