Thermal conductance switching based on the actuation of liquid droplets through the electrowetting on dielectric (EWOD) phenomenon

Thermal conductance switches enable active and reconfigurable thermal control and management for a wide variety of applications. We demonstrate a thermal conductance switch based on the actuation of liquid droplets in a co-planar electro-wetting-on-dielectric (EWOD) configuration. By eliminating the need for relative motions of two heat transfer surfaces, the device provides a significant advantage in the mechanical design of adaptive thermal control systems. Proof-of-concept devices are constructed and characterized to confirm the mechanism of droplet detachment and attachment for thermal switching. Numerical simulation is performed to elucidate the experimentally measured thermal performance and identify thermocapillary flows as an important contributor to heat transfer for certain dielectric liquids. The present work provides a proof-of-concept demonstration of novel thermal conductance switches and offers physical insights to help systematically design the switches for practical applications.