Dynamic behaviors and charge characteristics of droplet in a vertical electric field before bouncing

Abstract

Utilization of vertical electric field can depart water droplets from superhydrophobic surfaces, which has significant application in microfluidic and self-cleaning. Here, we studied the droplet jumping dynamics behavior in the electric field, which was applied by pulsed and direct current (DC) power. The results indicated the droplet can jump more rapidly under the pulsed electric field. Compared with the droplet under DC electric field, the response time of droplet before jumping under pulsed electric field can be reduced by at least 70%, and the threshold pulsed electric field for jumping can be reduced by 15%. The relationships between droplet dynamics behaviors and power output voltage have also been investigated. The results showed there exist three different jumping dynamic behaviors in the pulsed electric field. The droplet charged amount decreases with the increase of the pulsed electric field, but remains almost unchanged in the DC electric field. In the pulsed electric field, different jumping behaviors can affect the contact area and contact time of droplet, which is supposed to significantly affect the charge amount. The results revealed some important effects of output voltage on droplet jumping behavior, which could be helpful to step forward in the design of the electrically driven droplet-based systems.