Solvation forces in fluids

Abstract

Using a formalism derived by us in an earlier paper we obtain the density profile and solvation force between two identical hard plates separated by a fluid characterized by (i) an Orstein-Zernike correlation function and (ii) a Percus-Yevick sticky sphere correlation function. Example (i) yields an exponential or hyperbolic density profile characterized by a correlation length ξ that diverges at the critical point as (T-T_c )^-v . The corresponding force is weak and attractive following an exponential law at large separations. Example (ii) yields an attractive force in the vicinity of the critical region and an oscillatory force at higher densities and/or higher temperatures which can significantly modify forces between colloid particles.