Navigation of Droplets through Micropillars using an AC Electric Field

Abstract

We propose a new active mechanism to navigate droplets through a micropillar using an AC electric field. This mechanism enables on-demand droplet merging after head-on collision with a micropillar. In the absence of the electric field, droplets will split into two daughter droplets after collision with the micropillar. By passing an AC electric field across the micropillar, we observed that the electric field allows the split droplets to merge and revert back to become a single droplet. This new phenomenon opens up various exciting new possibilities such as digital signal encoding, generation of droplets of various sizes and droplet barcoding. We present here the preliminary experimental results obtained by varying both the applied voltages and frequencies.