Rapid gelation of mechanical robust, conductive, and self-healing lignocellulosic nanofibrils hydrogel toward flexible sensor over a broad temperature spectrum

Electronic devices based on soft hydrogels have potential uses in real-time physiological monitoring and enable early detection of disease. However, the main challenge is to simultaneously address the two conflicting issues of facile device integration capability and good overall performance, with simplicity of fabrication. Here we introduce a simple strategy using a dynamic oxidation-coordination system to create an all-in-one polymeric hydrogel that combines ease of processing, mechanical adaptability, self-healing, and strain-sensing, with a wide- temperature tolerance. The hydrogel undergoes very fast self-gelation (within a minute), and the integration of lignocellulosic nanofibrils (PLCNF), Fe3+/Zn2+ ions, and sorbitol results in exceptional properties including super high strength (0.67 +/- 0.04 MPa), stretchability (1803 +/- 120 %), high conductivity (1.59 +/- 0.10 S/m), and self- healing ability. This hydrogel platform can conform to limbs or skin for non-invasive continuous motion monitoring, or in health management. Its self-healing and temperature tolerance ensure stable sensing performance even when subjected to damage or under extreme conditions. Our work thus offers a novel platform for cost-effective, customized, multifunctional hydrogel materials, and thereby broadens the application of conductive polymer hydrogels.