A Tough, Adhesive, and Antifreezing Eutectic Organohydrogel for Wearable Sensing Toughened by Quaternary Ammonium Chitosan via Cation–Dipole Interactions

Hydrogel adhesives that simultaneously possess high toughness, strong interfacial adhesion, and freeze resistance are urgently needed for emerging flexible electronics and wearable devices. However, conventional hydrogels typically suffer from weak bonding to diverse substrates and brittle failure under subzero conditions. Herein, we present a cation–dipole-enhanced eutectic organohydrogel (APQ-DES) constructed via an interpenetrating network strategy using a choline chloride/glycerol deep eutectic solvent (DES) as the dispersion medium. The system combines chemically cross-linked polyacrylamide (PAM), poly(vinyl alcohol) (PVA), and cationic quaternary ammonium chitosan (QCS). The DES endows the hydrogel with excellent freeze tolerance, while synergistic cation–dipole interactions between QCS and various substrates, together with hydrogen bonding from PVA and PAM, enable robust adhesion across diverse materials, including PTFE, rubber, glass, and wood, achieving lap-shear strengths up to 584.57 kPa. The optimized APQ-DES hydrogel exhibits outstanding mechanical properties (tensile strength: 206.99 kPa, elongation at break: 1891%, toughness: 1.71 MJ·m –3 ), maintains flexibility and ionic conductivity at −20 °C, and functions as a reliable strain sensor with rapid response (361 ms), broad sensing range (0–400% strain), and stable cyclic performance. Demonstrations of multisite human motion monitoring under cold conditions highlight its potential for winter sports training evaluation, human–machine interfaces, and low-temperature wearable healthcare applications.