Modulation of electroosmotic flow through electrolyte column surrounded by a dielectric oil layer

The present study deals with the electroosmotic flow (EOF) through a column of an aqueous solution (medium of high dielectric constant) surrounded by an oil layer (low dielectric constant medium). The dielectric oil layer contains solubilized surfactants bearing additional mobile charges and the electrolyte medium comprises of binary symmetric electrolyte ions. A mathematical model based on Poisson-Boltzmann equation for induced potential and Stokes equation for fluid flow is adopted. The model assumes that the oil-electrolyte interface bears a nonzero surface charge and the electrolyte ions can penetrate across the interface. A semi-analytical method has been developed to study the modulation of EOF by considering the effect of partition coefficient of the electrolyte ions. The effect of concentration of mobile charges inside the oil layer and the interfacial charges on the modulation of EOF through such a system is investigated for a wide range of bulk electrolyte concentration.