The Ornstein-Zernike equation is used to analyze adsorption at, and the forces between, solutes and walls in near-critical fluids. The density profile is shown to decay exponentially with the bulk correlation length. The forces between solutes and between walls are also exponentially long ranged with the bulk correlation length, and are always attractive for identical solutes.

• Received 14 October 1991

DOI:https://doi.org/10.1103/PhysRevA.45.7621