Electrical Field Dependent Droplet Selector

Electric field effect on liquid drop rebounding is studied in interdigitated array (IDA) electrodes covered with superamiphiphobic coating under AC field. Coefficients of restitution are measured in different applied voltages. The results show that a medium voltage applied on IDA (~ 30V) can effectively change the drop rebounding on the IDA surface. We also directly measured the adhesive force curves and contact angles of drops on IDA under different voltages. The results suggest that only small fraction of the drop is tightly pinned on the surface while the other parts of the surface remain superhydrophobic. This new method of controlling liquid-solid interaction may enable new drop based microfluidic applications. A simple control of drop re-bouncing distance is also demonstrated.