(217co) Oxidative Surface Phenomena of Eutectic Gallium Indium

Phipps, D., North Carolina State University
Dickey, M. D., North Carolina State University

Eutectic gallium indium (EGaIn) is a metal alloy with a melting point of approximately 15°C and therefore is liquid at standard room temperature conditions. EGaIn forms a passivating oxide layer in the presence of oxygen. This thin oxide layer provides mechanical stability to the metal and allows it to be molded into non-spherical shapes, making it compatible with microfluidic systems and flexible electronic devices. The goal of this work is to describe new methods to control the way liquid metal flows and thereby change its shape. This work describes a new method to induce flow in the metal using only modest voltages, one to two volts. Under certain conditions the surface area of a drop of the liquid metal has increased two to three fold despite its large surface tension. This oxidative potential allows for the actuation of the liquid metal in microchannels without the need for internal moving parts.