The zeta-Potential of Silicone Oil Droplets Dispersed in Aqueous Solutions

An experimental method to measure the zeta-potential of small liquid droplets dispersed in another immiscible liquid was presented in this paper. Basically, a liquid droplet was held stationary in a test cell by applying a proper static electric field. An existing theory shows that the electrical force experienced by the droplet can be related to the zeta-potential of the liquid droplet. Thus the zeta-potential can be determined from the force balance among the electrical force, the gravitational force, and the buoyancy force being exerted on the stationary droplet. This electrical suspension method was applied to study the effects of pH values, ionic features, and concentrations of three electrolytes and two ionic surfactants on the zeta-potential of the silicone oil (No. 1) droplets. Copyright 1998 Academic Press.