From the ages of 14 to 18 I worked with Prof. Michael Dickey in NC State’s Chemical & Biomolecular Engineering department studying room temperature liquid metals. Our group specialized in an eutectic Indium and Gallium alloy (EGaIn) that remained liquid under room temperature. In addition to its liquidity, EGaIn has the unique ability to spontaneously form a solid oxide layer when exposed to the atmosphere. Our work primarily focused on exploiting these unique physical and chemical properties to produce novel materials.
In my first two years in the lab, I worked with a graduate student to produce polymer encapsulated liquid metal droplets via a flow-focusing, a microfluidic particle generation technique. In the years following, I began working independently to produce liquid metal thin films on copper substrates. My work primarily focused on adopting electrophoretic deposition, a process commonly used in ceramics processing, to EGaIn nanoparticles. I’ve presented this work at both undergraduate and graduate research conferences. An abstract of my work can be found below as well as links to a full paper and poster.
Abstract
This work discusses a novel method to deposit thin films of a liquid metal, eutectic gallium‐indium (EGaIn), on a copper substrate through electrophoretic deposition (EPD). The EPD procedure involves the application of an electric field in the range of 200-250 V/cm to an isopropyl alcohol solution containing a charging salt (0.108 M MgSO 4 ), and EGaIn nanoparticles (0.03 g/L). These experimental conditions were found to form a conductive liquid metal layer approximately 10-20 μm thick with a naturally forming solid oxide skin on EGaIn, adding enhanced mechanical stability and self-healing characteristics to the liquid film. Optical profilometer analysis of the thin films revealed a rough surface morphology as a result of the oxide layer. Film thickness and mass were found to be strongly connected to EGaIn concentration in solution, charging salt concentration, environmental temperature, and EPD duration. Specifically, film thickness was directly correlated to EGaIn concentration and EPD duration. This work has implications in flexible electronics and other circuitry as a novel self- healing and conductive agent to repair damaged electrical circuits.
