We 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.