Electrothermally induced flow in AC EWOD droplet

TL;DR

This paper introduces a novel electrothermal actuation method for droplets under AC electrowetting, enabling strong internal fluid motion at low voltages, with potential applications in micromixing.

Contribution

It demonstrates a new electrothermal flow mechanism in droplets using low voltage AC electrowetting, supported by experimental and numerical analysis.

Findings

High fluid velocities of mm/s achieved inside droplets.

Electrothermal motion generated at voltages below 10V.

Parametric study guides optimization for micromixer design.

Abstract

We show a novel way of generating electrohydrodynamic motion inside a droplet under AC electrowetting. Using a very low applied voltage (10<V) strong electrothermal motion can be generated in the droplet. Alternating current electrothermal (ACET) actuation originates due to imposed Joule heating into the fluid body via applied electric field. A parametric study based on operating parameters and geometrical parameter is conducted experimentally and numerically. With the operating ranges of parameters, high fluid velocity of the order of mm/s can be generated inside the droplet. Further improvement in fluid motion can be anticipated through optimization technique. The investigations revealed in the analysis can be used as useful tool in the design of efficient drop-based micromixer.