Versatile carboxymethyl cellulose-based pH responsive hydrogel with robust mechanical strength, adhesion, and self-healing for motion monitoring and touchscreen interaction.

Abstract

Hydrogels exhibiting functional properties like mechanical strength, self-healing ability, strong adhesion, and reliable sensing performance remains a major challenge for wearable electronics. Herein, a sustainable biomass-derived CPAT hydrogel was fabricated from carboxymethyl cellulose (CMC), poly(vinyl alcohol) (PVA), acrylic acid (AA), and tannic acid (TA) through UV-induced polymerization and supramolecular crosslinking. The cooperative integration of a poly(ethylene glycol)diacrylate crosslinked poly(acrylic acid) (PAA-PEGDA) network with dynamic hydrogen-bonding interactions generated a robust multi-network architecture. This material exhibited good stretchability, high tensile strength, and toughness. Furthermore, the hydrogel demonstrated efficient self-healing with a healing efficiency exceeding 90%, an elastic recovery of approximately 90%, and 96% stress retention after repeated deformation cycles. The hydrogel displayed strong universal adhesion, pronounced pH-responsive swelling and sensing behaviour. Electrochemical impedance spectroscopy revealed an ionic conductivity of 3.33 × 10--2 S cm-1, while stable sensing performance was maintained over 1000 loading-unloading cycles. The hydrogel enabled real-time monitoring of human motions and good physiological activities, including swallowing and speech-related throat movements. The material exhibited excellent cytocompatibility, maintaining approximately 93% viability of L929 fibroblast cells. These results show the potential use of CPAT hydrogel as a multifunctional platform for wearable sensors, human-machine interfaces, and intelligent healthcare application.