INTEGRAL-EQUATION THEORY FOR HIGHLY ASYMMETRIC ELECTROLYTE-SOLUTIONS

Integral equation theory based on the Wertheim's two density formalism is proposed to study interactions in highly asymmetric electrolyte (polyelectrolyte) solutions. The aqueous solution contains large and highly charged polyions and small counterions having one elementary charge. The potential energy of interaction between counterions and polyions is divided into two parts, a strongly attractive part responsible for association and a nonassociating part. Due to strong asymmetry in size we can treat the counterions as singly bondable, while each polyion may bond to several counterions. The two density theory yields very good agreement with new and existing computer simulations for these systems. This good agreement is extended into the region of parameters where ordinary HNC approximation does not give a convergent solution.