Capillary meniscus interaction between a microparticle and a wall

An analytical expression for the shape of the capillary meniscus formed around a vertical cylinder or spherical particle near a vertical wall is derived by using the method of matched asymptotic expansions. The forces of capillary interaction between the particle (cylinder) and the wall are calculated. The resulting expressions are valid when the distance between the particle (cylinder) and the wall, as well as the particle radius, are much smaller than the capillary length. This range corresponds to colloidal and micron-size particles. The theory predicts attraction between such a particle and the wall. The results can be useful for a better understanding of processes such as surface coagulation and two-dimensional ordering of colloidal particles or protein molecules attached to a fluid interface.