Stability of emulsions of water in oil. II. Charge as a factor of stabilization against flocculation

Abstract

It is shown by theoretical calculations that the energy barrier between charged droplets in water-in-oil emulsions is strongly diminished when the concentration of the emulsion is not extremely low. This is a consequence of the great extension of the diffuse electrical double layer in oil. The high concentration in the sediment (or cream) therefore strongly promotes flocculation. Gravity also promotes flocculation directly in all but the most dilute W/O emulsions because the weight of the particles in higher layers transmitted by the extended double layers presses on those in the lower layers and forces them together.