Droplet dynamics in a microchannel subjected to electrocapillary actuation

Abstract

In this paper, a theoretical approach is devised to analyze the droplet dynamics in a microchannel subjected to electrocapillary actuation mechanisms. Specific attention is devoted to estimate the influences of the applied potentials and the hydrophobic insulation thicknesses, so as to obtain suitable interelectrode spacings, for a given droplet size. It is revealed that there exists a threshold limit on the value of the interelectrode pitch, beyond which the overall microfluidic transport rates are substantially lowered. On the other hand, with interelectrode spacings below the threshold limit, unnecessarily large number of electrodes might be necessary to achieve a desired droplet transport. Further, the optimal interelectrode spacings are found to be strong functions of the applied potentials and the dielectric layer thicknesses, based on which suitable design guidelines can be proposed.