CAPILLARY MENISCUS INTERACTION BETWEEN COLLOIDAL PARTICLES ATTACHED TO A LIQUID-FLUID INTERFACE

General expressions for the energy of capillary meniscus forces acting between particles attached to a liquid-fluid interface are derived. These expressions are specified for the cases of two vertical cylinders and two similar spheres partially immersed in a liquid layer on a horizontal solid substrate. The shape of the meniscus around the particles is determined from the Laplace equation by using the method of the matched asymptotic expansions. The derived asymptotic expressions are valid with a very good accuracy when the contact line radius and the interparticle distance are smaller than 100 μm (liquid-gas interface). The range of validity can be wider for emulsion-type interfaces. The capillary meniscus forces turn out to be attractive and very long-ranged. The results can be important for interpreting the surface coagulation phenomena accompanying flotation processes as well as two-dimensional ordering of colloidal particles and protein molecules. © 1992.