Interfacial effects in solids-stabilized emulsions: measurements of film tension and particle interaction energy

The extent of the stability of solids-stabilized emulsions depends on the resistance offered by the interfacial layer of particles to coalescence. An experimental technique is described to study the effect of interfacial layers of hydrophobic particles on the process of coalescence of a water drop at a planar oil/water interface. The influence of interfacial solids packing density on the film tension and particle interaction energy was investigated for two hydrophobic solids. Dust particles filtered from shale oil formed periodic structures at the interface and the film tension and particle interaction energy exhibited multiple maxima and minima. Spherical glass beads (4 μm diameter) coated with asphaltic matter, on the other hand, displayed a single maximum in particle interaction energy around monolayer coverage.