Transparent, Tough, Self-Adhesive, and Antifreezing Ionic Conductive Organohydrogel for Flexible Sensing

Ionic conductive organohydrogels have attracted significant attention in wearable sensing due to their transparency, conductivity, and flexibility. However, simultaneously achieving outstanding mechanical performance, freezing resistance, and strong interfacial adhesion within a single ionic organohydrogel remains a significant challenge. Herein, we developed a tough, antifreezing ionic organohydrogel by integrating polydopamine (PDA) and Al3+ into a poly(acrylic acid) (PAA)/gelatin hybrid network in a water/glycerol binary solvent system. Dynamic noncovalent and coordination interactions reinforce the polymer network, whereas the water/glycerol binary solvent system imparts freezing resistance, collectively enabling the PAA/gelatin/PDA/Al3+ (PGDA) organohydrogel to integrate mechanical robustness with multiple functionalities. The resulting organohydrogel achieved good stretchability (724%), high toughness (1.39 MJ m–3), and a strain-recovery ratio exceeding 95% after 300% deformation. Moreover, the hydrogel exhibits high conductivity (1.2 S m–1), optical transparency (>90%), antifreezing (−20 °C, 0.67 S m–1), and strong adhesion (73.56 kPa). The flexible sensor fabricated by the PGDA organohydrogel exhibited high strain sensitivity (gauge factor, GF = 4.11), enabling effective monitoring of various human joint movements and handwriting-induced signal recording. Notably, the sensor retained stable motion-sensing performance under subzero conditions (−20 °C), highlighting its potential for flexible electronics and wearable sensing in cold environments.