The Effect Of Specific Conductivities of Oil and Water Phases on the Critical Voltage of Emulsification

Abstract

The electric emulsification by the use of high voltages has been carried out to produce aerosols. However, , the present authors succeeded in producing directly O/W or WIO type emulsions by using fairly low voltages, during the course of studies on electrocapillary phenomena at oil/water interfaces. The critical voltage of emulsification E., i. e. the minimum voltage necessary to produce a continuous emulsification, had no direct relationship with the equilibrium interfacial tension r measured by the ordinary drop-weight method. Concentrations of inorganic electrolytes and ionic surface active agents in the oil and/or water phases had strong influences on Ee. The effect of the concentration of surface active agent, however, was found to be due primarily to its property as an electrolyte, the surface activity playing the secondary role. lt is the necessary condition for the electric emulsification that the specific conductivity of the discontinuous phase is higher than that of the continuous phase. Ne emulsification takes place when the latter is higher. Although the experiments were maiRly carried out in the waterlfuethylisobutylketone system, the same condition can be applied to other systems. For instance, mercury/water and liquid/air (aerosols) systems, for which most studies on electric emulsification were carried out, also satisfy this condition.