Associating polyelectrolyte solutions: Normal and anomalous reversible gelation

An equilibrium mean-field theory for dilute polyelectrolyte solution with many associating groups per chain is presented. We have shown that in addition to physical gel formation, the aggregation of polyelectrolyte chains in dilute solution can lead to the formation of optimum size clusters. The physical reason for the stabilization of such clusters is discussed. Intramolecular optimum cluster formation (necklace conformation) becomes possible for long or charged enough chains. The study of influence of the number of stickers on phase behavior of associating polyelectrolyte solution enabled us to predict a rather unusual counterintuitive effect: The physical gel formation can be induced by the decrease of the number of stickers (anomalous physical gelation). This effect has pure polyelectrolyte nature and is connected with the translational entropy of mobile counterions. (C) 2001 American Institute of Physics.