THERMODYNAMIC PERTURBATIVE APPROXIMATION FOR CHARGED COLLOIDAL SUSPENSIONS

A density functional perturbative approximation, which is based on bot h the weighted-density approximation of Tarazona and the density funct ional approximation of Rickayzen et al., has been developed to study t he structural properties of charged colloidal suspensions with the lon g-range repulsive part of potential. The two-particle direct correlati on function, which is based on the rescaled mean spherical approximati on, has been used to calculate the local concentration profiles of hig hly charged colloidal suspensions near a highly repulsive wall and con fined between highly repulsive silt walls. The calculated results show that for smaller wall-to-wall separations the present approximation i s a significant improvement upon those of the hypernetted chain functi onal approximation and compares well with the computer simulation. How ever, the qualitative differences between the present approximation an d the hypernetted chain functional approximation decrease with increas ing wall-to-wall separations.