High-degeneracy ordering of polyampholyte gels from a random-field model

Abstract

Experiments have yielded multiple coexistence loops for gels with random positive and negative ionic groups, exhibiting the existence of up to seven distinct macroscopic phases distinguished by volume discontinuities. We introduce for this system a model composed of local degrees of freedom for ionization and for ionized cross-binding which are spatially arrayed with random connectivity. This model yields the multiple coexistence of phases, as well as volume versus excess charge curves, similar to the experimental results.