Swelling and thermally stimulated depolarization currents in hydrogels formed by interpenetrating polymer networks

Polymer hydrogels have been prepared whose hydrophilicity is determined by the relative amounts of the component polymers, in the form of interpenetrating networks of a hydrophobic and a hydrophilic constituent. Equilibrium water contents, diffusivity of water and water sorption isotherms have been measured as a function of xerogel composition. Thermally stimulated current spectra have been measured for each xerogel composition at a series of different hydrogel water contents, and the effects of water on the relaxations of the polymer have been studied. The set of results suggests that the interpenetrating polymer networks (IPNS) are phase-separated systems with hydrophilic domains behaving essentially as does the pure hydrophilic component polymer. (C) 1998 Elsevier Science B.V. All rights reserved.