Electrostatic control of droplets on lubricated surfaces at ultra-low voltage

We demonstrate droplet manipulation under ultra-low voltage (1.5 V) by combining surface lubrication with electrostatic control. By introducing silicone oil layers on solid surfaces, we transformed liquid–solid friction into liquid–liquid friction, with optimal performance achieved at ∼100 μm thickness. Our findings confirm electrostatic forces, not contact angle changes, as the primary driving mechanism, with droplet velocity directly correlating with charge. We identified competitive interactions between electrostatic and dielectrophoretic forces at electrode gaps and developed a two-stage driving method that strategically switches between dual- and single-electrode configurations to overcome dielectrophoretic limitations. This approach enables complete droplet movement between electrodes at voltages an order of magnitude lower than conventional electrowetting techniques, offering new possibilities for energy-efficient microfluidic devices and portable lab-on-chip applications.