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 (p olyelectrolyte) solutions. The aqueous solution contains large and hig hly charged polyions and small counterions having one elementary charg e. The potential energy of interaction between counterions and polyion s is divided into two parts, a strongly attractive part responsible fo r association and a nonassociating part. Due to strong asymmetry in si ze we can treat the counterions as singly bondable, while each polyion may bond to several counterions. The two density theory yields very g ood agreement with new and existing computer simulations for these sys tems. This good agreement is extended into the region of parameters wh ere ordinary HNC approximation does not give a convergent solution.