CAPILLARY INTERACTION OF SPHERICAL-PARTICLES ADSORBED ON THE SURFACE OF AN OIL-WATER DROPLET STABILIZED BY THE PARTICLES .1.

The capillary interaction energy between identical spherical particles adsorbed as a monolayer on the surface of an oil/water emulsion droplet stabilized by the particles is determined. Use is made of the theoretical work by Menon, Nagarajan and Wasan on the free energy change due to the adsorption of the particles on the droplet from the continuous phase. It is assumed that the oil/water interfaces joining neighboring adsorbed particles are portions of spheres with a common radius and a common center. The capillary interaction between the particles is indirectly taken into account through the change in radius of the droplet on the adsorption of the monolayer of particles. The capillary interaction is obtained as the difference between two large energies of the order of 10(6) kT per particle which are almost equal. Hence that part of the adsorption energy attributed to a particle which excludes its interactions with neighboring adsorbed particles must be clearly identified. The capillary interaction is attractive and is comparable with a multiple of kT, diminishing as the inverse square of the separation between the particles and proportional to the fourth power of the particle radius.