Theory of volume transitions in polyelectrolyte gels

Abstract

ABSTRACTWe present the key assumptions and results of a newly developed theory in order to account for the self-consistent cascade effects of counterion condensation and volume collapse of polyeletrolyte gels. In the present theory, the role of the specificity and valency of counterions on the volume transitions are also treated. These features and the fluctuations of monomer concentration and local electrolyte charge density are included on top of the familiar features of the Flory-Huggins theory and the classical rubber elasticity theory in the previously used Flory-Dusek-Patterson-Tanaka theory of polyelectrolyte gels. We have computed the swelling equilibria by satisfying the multicomponent nature of the system and the Donnan equilibria. A few major effects are illustrated in terms of the dependence of volume transition on the solvent quality, temperature, salt concentration, valency and specificity of the counterion, and polymer charge density. Criteria for the emergence of a reentrant volume transition are also derived.