Dynamic and equilibrium swelling behaviour of pH-sensitive hydrogels containing 2-hydroxyethyl methacrylate

Abstract

This chapter describes the dynamic and equilibrium swelling behavior of pH-sensitive hydrogels containing 2-hydroxyethyl methacrylate. Hydrogels may be sensitive to their environment and their structure may change according to the conditions around them. They are potentially useful materials in biomedical applications. Hydrogels are particularly promising because of the similarities between their physical properties and those of living tissue. The equilibrium and dynamic swelling behavior of hydrogels containing methacrylic acid or various acrylamides has been studied as a function of copolymer composition. In all cases, the comonomer was 2-hydroxyethyl methacrylate, methyl methacrylate, or N-vinyl-2-pyrrolidone. It is shown that pH-sensitive behavior with a wide range of swelling ratios could be obtained using a range of compositional changes. The dynamic swelling behavior was a function of the acidity of the buffered solution. Furthermore, it has been shown that pH-sensitive hydrogels can be prepared by incorporation of moieties with carboxylic groups, or moieties with acrylamide, or simply by drastic change of the hydrophilicity of one moiety. These hydrogels show significant dependence on pH and ionic strength.