Zx. Tang et al., EFFECTS OF SOLVENT EXCLUSION ON THE FORCE BETWEEN CHARGED SURFACES INELECTROLYTE SOLUTION, The Journal of chemical physics, 100(6), 1994, pp. 4527-4530
Effects of hard-core exclusions of solvent molecules on the force betw
een charged surfaces immersed in electrolyte solution are investigated
theoretically. A three-component model of electrolyte solution is use
d, in which the solvent is modeled as a fluid of neutral hard spheres.
A free energy density functional theory, which has been applied previ
ously to Study the interaction between primitive electrical double lay
ers, is extended to include ion-solvent and solvent-solvent interactio
ns. Hard-core correlations are incorporated in a nonlocal free energy
density functional, while electrostatic correlations are evaluated usi
ng the mean spherical approximation. The force between charged surface
s as a function of surface separation is found highly oscillatory, wit
h a period approximately equal to the particle diameter. Because of th
e dominant role of the hard-core exclusions of the solvent fluid, the
force does not depend strongly on either electrolyte concentration or
surface charge density.