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Gallium-Indium Liquid Metal Self-Healing Electronics, Part 2 of 5

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  • Yesterday Eric Markvicka demonstrated self-healing electronics for us with his video of a liquid metal embedded elastomer. Today, we discuss a composite material that is electrically insulating until it is patterned, at which point it becomes conductive. What initially drew my attention to this technology is that it contains indium and gallium, specifically EGaIn – the eutectic gallium-indium alloy (Indalloy #60) which is 75.5%Ga and 24.5%In.

    Jim: Could you tell us about this material?

    Eric: The rubber composite is composed of microscopic droplets of eutectic gallium-indium embedded inside of a soft silicone rubber. In contrast to most particle-filled composites, the liquid-phase composite is softer than the unfilled rubber ,and is electrically insulated after it has cured, even for high volume loadings (up to 50%). 

    Jim: Was this the first time you worked with liquid metal (gallium-indium)?

    Eric:  No, liquid metal (gallium-indium) was used in several of my recent projects. I've used liquid metal (gallium-indium) to increase the dielectric constant of soft silicone elastomers while preserving the mechanical properties of the host elastomer for electrical wiring in soft-matter printed circuit boards. Here we patterned the liquid metal (LM) circuit wiring using UV laser micromachining [DOI: 10.1021/acsami.7b05522], and most recently we were able to create visually imperceptible, stretchable LM circuit wiring for use in a heads up display to warn of potential environmental hazards.

    Jim: I have some papers to check out! Tomorrow we’ll be back, discussing how easy it is to make these flexible circuits using a commercially available plotter. We’ll see you then…

    (The electrically self-healing liquid metal-elastomer composite is detailed in Nature Materials)