High-performance conductive eutectogel synthesized by carboxymethyl cellulose-enhanced physicochemical dual network...

Hydrogels have garnered considerable attention in wearable devices due to their tunable mechanical properties. However, their applications are constrained by limited conductivity and inadequate freeze-resistance. In this study, we develop a physical-chemical dual network eutectogel (PECA/CMC_X) through a synergistic enhancement strategy combining the multiple hydrogen bonds of carboxymethyl cellulose sodium (CMC) with metal-ion coordination within a deep eutectic solvent (DES). The eutectogel incorporates a physically cross-linked CMC network with a chemically cross-linked polyacrylamide (PAM) network via multiple non-covalent interactions (e. g., hydrogen bonds) and covalent bonds formed through free-radical polymerization. PECA/CMC_1.35 eutectogel exhibits superior mechanical properties, a fracture toughness (29.22 kJ·m^-3) and a high tensile stress (23.8 kPa). Owing to the carboxyl-metal ions coordination and the freezing-point depression effect of DES, the eutectogel maintains a high conductivity of 0.35 S·m^-1 at -20 °C. When employed as an electrolyte in a supercapacitor, it exhibits stable cycling performance, retaining 79.4% of its initial capacitance and a Coulombic efficiency of 92.3% after 2000 cycles. As a strain sensor, the eutectogel achieves a gauge factor (GF) of 1.06 over a range of 40-200%. This work introduces a sustainable synergistic design strategy for multifunctional eutectogel suitable for flexible electronic devices under extreme conditions.