Microscopic simulation of phase transition in interacting ionic gels

Ionic polymer networks are studied using the bond fluctuation method. Gels are known to exist in expanded or collapsed phases as demonstrated by Tanaka et al.’s experiments on ionic gels. Two interactions—the quality of the solvent and the work done by a gas of counterions—suffice to characterize the first-order phase transition indicated in these two-dimensional simulations. A technique is introduced which prevents local attractive interactions from hindering global relaxation.