Multifunctional Liquid Metal-Based Nanocomposite Hydrogel with High Conductivity, Antibacterial and Adhesive Properties for Wearable Electronics

The emergence of eutectic gallium–indium (EGaIn) liquid metal (LM) alloys as a soft multifunctional nanofiller presents an opportunity for the fabrication of hydrogel-based strain sensors with advanced multifunctional properties. However, developing a facile and efficient approach to synthesize nanocomposite conductive hydrogels that exhibit excellent stretchability, conductivity, self-adhesion, and antibacterial properties remains a significant challenge. In this study, we introduce a semi-interpenetrating network design strategy to synthesize a high-performance nanocomposite hydrogel [liquid metal/silver nanowires/sodium lignosulfonate/polyacrylamide] [LM/AgNWs/SL/pAM] (LASM). This hydrogel consists of a single polyacrylamide (pAM) network combined with a semi-interpenetrating network formed by silver nanowires (AgNWs) and LM nanoparticles. The semi-interpenetrating network is primarily cross-linked through hydrogen bonds, electrostatic interactions, and metal coordination. The resulting conductive hydrogels demonstrate superior stretchable properties (tensile stress: 120.28 kPa; tensile strain: 373.15%), impressive conductivity (0.64 S/m), high antifatigue performance, self-adhesive characteristics (Ti: 25.40 kPa; Al: 20.66 kPa), and notable antibacterial activity, all achieved through the construction of a hybrid chemical and physical cross-linking network. Leveraging these attributes, the nanocomposite hydrogel was assembled into a flexible sensor capable of distinguishing an extensive range of human movements, from large scale motions to subtle joint bending with remarkable stability and sensitivity. Furthermore, the LASM strain sensor can function as an adaptable writing keyboard that accurately recognizes English letters (“a”, “p”, “e”, “L,” and “HUT”) in real time when written on its surface. This multifunctional 3D nanocomposite conductive hydrogel holds great potential for applications in wearable electronics.