This project involved transforming eutectic gallium indium (eGaIn), a type of liquid metal alloy, into an emulsion that could be chemically activated. EGaIn, in its natural liquid form, is a good conductor of electricity while being stretched. Liquid metal emulsions (LMEs) are a type of material composite that transforms the liquid metal into droplets within another liquid, giving it different material properties compared to its natural from.
When eGaIn is transformed into an LME, however, it loses its electrical conductivity because droplets are encased in an oxide skin, which has higher electrical resistance than the pure liquid metal. Thus, the LME requires activation (i.e, making the LME conductive again through droplet coalescence). Our group came up with the first liquid metal emulsion formulation that uses a chemical ingredient that that removes the oxide through acid etching. We also show that it could be used in 2D/3D printing techniques, and that it could also be applied to the automated fabrication of electronics using liquid metals.
Press: Self-Catalyzed Chemically Coalescing Liquid Metal Emulsions (paper)