Liquid-metal Devices And Circuits For Thermal Applications And Communications

Abstract

The unique properties of liquid metal, such as high electrical conductivity, high thermal conduc-tivity, and deformability, offers promising opportunities for emerging devices and circuits. The focus of this thesis is on actuating liquid metal for potential applications in hot-spot cooling, sens-ing, and communications. First, continuous electrowetting of a liquid-metal droplet is demon-strated for controlled two-dimensional actuation and selective hot-spot cooling. In a 3 cm  3 cm well, a Galinstan liquid-metal droplet could move at a terminal velocity of 13.3 cm/s with an ac-tuation voltage of 11 V DC. For an actuation voltage of 10 V DC, the liquid-metal droplet de-creases the temperature of a localized hot spot by approximately 7 °C. Next, controlled defor-mation of liquid metal by electrocapillary actuation is demonstrated in fluidic channels at the sub-millimeter-length scale. In 100-µm-deep channels of varying widths, the Galinstan liquid metal could move at velocities greater than 40 mm/s. The dynamic behavior and physical limitations of the liquid metal as it moves in the fluidic channels is described and is useful for designing mi-crosystems that use liquid metal as a functional material.