Superstrong and Tough Biomimetic Lignin‐Based Hydrogel Enabled by Self‐Diffusion Driven Strategy for Self‐Powered Human Dynamic Healthcare Monitoring

ABSTRACT Biomass‐based hydrogels are widely regarded as ideal substrates for self‐powered wearable sensors. However, the practical applications of hydrogels are commonly limited by their inherent low strength and toughness, which restrict their capacity to withstand repeated stretching, bending and other mechanical loads arising from human motion in wearable device scenarios. Inspired by the natural lignocellulosic architecture of plant cell walls, this study devised a biomimetic molecular engineering strategy for fabricating a novel lignin‐based hydrogel via the gradual self‐diffusion of sulfonated and demethylated modified lignin (SDL) into a polyvinyl alcohol (PVA) solution. Simulation and characterisation results demonstrated that the cross‐linked network and mechanical performance of the hydrogels were primarily governed by the formation and gradual densification of robust crystalline domains induced by SDL. The optimised lignin‐based hydrogel (SDLP‐ST48, soaking time 48 h) exhibited excellent mechanical performance, demonstrating a stress of 22.1 MPa, strain of 530%, Young's modulus of 19.6 MPa and toughness of 59.1 MJ m −3 . The self‐powered wearable sensor fabricated using SDLP‐ST48 displayed a high response speed (82 ms), rapid recovery (67 ms) and excellent stability over 900 cycles. Furthermore, five self‐powered sensors were integrated into the fingertips of a robotic hand. The multichannel intelligent sensing system exhibited an output signal recognition accuracy of 97% for eight unknown objects. Overall, this study provides new insights for addressing the key issues associated with the synthesis and application of high‐strength hydrogels.