Electrohydrodynamic deformation and interaction of microscale drop pairs

Abstract

Binary drop electrocoalescence is the process of inducing two drops, suspended in an immiscible fluid, to coalesce in the presence of an external electric field. Electric forces have been known to accelerate the rupture of the interfacial film and enhance drop coalescence but the process has not been well characterized. The effects of the drop ion concentration and interfacial tension on the coalescence process are studied. It is shown that increasing interfacial tension, along with electric field makes it more likely that the drops stabilize after coalescence, as opposed to breaking up. This is due to the relative magnitudes of the drop deformation and charge separation timescales.