Electric control of dielectric droplets and films

Abstract

We investigate the behavior of dielectric droplets and films placed onto a solid surface under the action of electric field of different configurations. The mesoscopic thermal multiphase lattice Boltzmann model [A. Kupershtokh, D. Medvedev, and I. Gribanov, "Thermal lattice Boltzmann method for multiphase flows,"Phys. Rev. E 98, 023308 (2018)] is used for simulation. Different configurations of electric field were produced by using dissected flat electrodes of various shapes. On a simple flat electrode, droplets elongate after the application of electric voltage. Quite different behavior was observed when the central round part of the electrode was made non-conductive. In this case, the droplet spreads under the action of a non-uniform electric field, and the breakup and the formation of an annular structure were observed. A film of dielectric liquid flowing along a solid surface made of conductive and non-conductive transversal stripes exhibits a variety of regimes. When the voltage is low, the action of electric field produces waves at the surface of liquid. At a high voltage, the liquid is pinned to the edges of stripes, and the flow may be stopped completely. The purpose of this article is precisely to attract experimenters to the study of this type of phenomena.