Coarse-grained potential for interaction with a spherical colloidal particle and planar wall

Abstract

An effective coarse-grained interaction potential between a point particle and a spherical colloidal particle with continuously distributed inverse power-law interaction sites is derived. The potential covers all ranges of spherical particle size, from a point particle up to an infinitely large particle forming a planar surface. In the small size limit, the point-to-point interaction is recovered, while in the limit of an infinitely large sphere the potential comes over to the known particle–wall potentials as, e.g., the 9–3 potential in the case of the Lennard–Jones interaction. Correctness and usefulness of the derived potential is exemplified by its application to SPC/E water at a graphite sphere and wall.