Liquid metal-gel (LM-Gel) with conductivity and deformability†

Abstract

Liquid metals (LMs), such as gallium and gallium-based alloys, have received considerable attention in various fields, such as soft robotics, skin electronics, and implantable electronics, owing to their extreme conductivity and deformability. However, the fluidity limits the ability of LMs to be used independently in stable devices to perform various functions; moreover, owing to their high surface tension, LMs cannot be easily dispersed in polymer networks to form a continuous phase. Accordingly, a type of LM-Gel is presented wherein LM infiltrates a polymer network. In this study, an Ag flake was used as the bridge between a LM and a polymer, modified on polyvinyl alcohol (PVA) to construct hydrophilic polymer–metal binary cooperative LM-philic networks, thus allowing a stable dispersion of the LM and increasing the mass content of the LM-Gel to approximately 92.86% based on the affinity between the LM and the Ag flake. The modified PVA acts as a soft network to bind the LM continuous phase. Based on this structure, LM-Gel exhibits low initial resistance (the resistance of its natural or original state following synthesis). Furthermore, LM-Gel has excellent molding and remolding abilities, which enable the fabrication of complex circuits or devices. In addition, the possibility of using LM-Gel as ink is investigated. The LM-Gel would potentially be useful for soft robots, wearable devices, and 3D printing.