Electric-field-controlled motion of liquid droplets on the surface of dielectric films

Kinetics of water droplets on the surface of shielded metal electrodes is studied in the presence of external electric field. It is shown that the difference of contact angles of droplet fragments on the control electrodes plays the key role in motion. It is also shown that a droplet always moves toward the negative electrode regardless of the polarity of control electrodes and grounding for the dielectric system under study. The theoretical analysis of the results is based on the Lippmann equation written for a polarized droplet that is localized on control electrodes shielded with a multilayer insulator.