Biomass-derived CMC-reinforced zwitterionic organohydrogel for wearable strain sensors: Achieving superior stretchability, adhesion, and anti-freezing performance.

Hydrogels have attracted significant attention in wearable electronics owing to their flexibility, biocompatibility, and responsiveness. However, simultaneously achieving strong adhesion, high stretchability, anti-freezing capability, and long-term stability remains challenging. Herein, we present a multifunctional organohydrogel synthesized via one-pot radical polymerization of sulfobetaine methacrylate (SBMA) and acrylic acid (AA) in the presence of biomass-derived carboxymethyl cellulose (CMC). The incorporation of CMC established abundant hydrogen bonding and secondary crosslinking interactions, thereby enhancing both mechanical strength and adhesion. Furthermore, the use of a binary ethylene glycol/deionized water solvent and lithium triflate significantly improved environmental tolerance and durability. The resulting organohydrogel exhibits exceptional stretchability (a fracture strain of 2729 % and a tensile stress of 218 kPa), strong adhesion (447 N/m on glass, 197 N/m on pigskin), superior anti-freezing capability (remains unfrozen at -70 °C), and stable mass retention (95 % after one week). It also demonstrates robust performance under repeated loading-unloading cycles (over 500 cycles), ensuring reliable, long-term signal stability. These balanced and enduring properties make the organohydrogel a promising candidate for wearable strain sensors, enabling precise and stable human motion monitoring even under extreme conditions.