Droplet Jumping From Superhydrophobic Surface Using Electrowetting

Droplet detachment from a superhydrophobic surface of coplanar electrodes-configuration were demonstrated in both air and liquid environment. Jumping height of the droplet was investigated as a function of applied potential and the AC pulse width. Both the base radius and the jumping height of the droplet under a certain voltage was found to be strongly affected by the AC pulse width. The optimum pulse width was found to be reasonably captured by the Rayleigh’s frequency but hardly affected by the amplitude of the voltage applied. Due to AC-induced oscillation, the voltage-off base radius of the droplet was observed to correspondingly change with the pulse width within the resonant time of the droplet. From the perspective of conversion between interfacial energy and kinetic energy, we developed a simple spherical configuration that correlates the jumping height with the base radius and the pulse width. The model captures the general trend between the three parameters, furthermore, it successfully predicts the periodical decay of the droplet jumping height in decane observed in our experiments.