Electro-osmotic control of the interface position of two-liquid flow through a microchannel

This paper presents theoretical and experimental investigations of the pressure-driven two-liquid flow in microchannels with the AN electro-osmosis effect. For fully developed, steady state, laminar flow of two liquids under the combined effects of pressure gradient, electro-osmosis and surface charges at the liquid-liquid interface, we have derived analytical solutions that relate the velocity profiles and flow rates to the liquid holdup, the aspect ratio of the microchannel, the viscosity ratio of the two liquids and the externally applied electric field. It was shown that adjusting the externally applied electric field could control the fluid interface position precisely. The prediction from the proposed model compares very well with measured data.