Hysteresis-free, fatigue-resistant and self-adhesive conductive hydrogel electronics towards multimodal wearable application

Conductive hydrogel-based electronic skins (e-skins) have attracted great attentions in health monitoring, human-machine interactions, and soft devices. Yet, broad challenges still remain in manufacturing of high-performance units, ingenious assembly of devices and developing of multimodal applications. Here, a typical strategy of combined covalent crosslinking and dynamic non-covalent interaction (multiple hydrogen bonds and electrostatic complexation) is used to prepare the ultra-durable polyacrylic acid (PAA)/ chitosan (CS)/ Ti3C2Tx (MXene) conductive hydrogel. It exhibits matched modulus for human skin, subtle mechanical hysteresis behavior (eta=0.27% of 200% stretch, energy loss coefficient), great fatigue-resistant stability (>99%, 400% strain), robust interface adhesion (similar to 30 kPa) and essential biocompatibility. Benefited of such high performance, a series of hydrogel-based devices are further assembled to demonstrate the multi-mode and multi-scenario applications, including the strain and temperature sensors, triboelectric nanogenerator. Clearly, thereby this work provides a new toolbox for the rational design of high-performance hybrid hydrogel, and points out a general route for further hydrogel-based device assembly and multimodal applications.