Construction of environmentally stable self-adhesive conductive cellulose hydrogel for electronic skin sensor via autocatalytic fast polymerization strategy at room temperature

Bio-based conductive hydrogels are catching a widespread attention in the field of flexible sensors and human-machine interface interaction. Here, an enhanced autocatalytic system constructed from dopamine-encapsulated cellulose nanofibers (DA@CNF) and Cu²⁺ in a glycerol-water binary solvent achieved fast auto-polymerization of hydrogels within 60 s. X-ray photoelectron spectra (XPS), UV-vis spectrum (UV), Cyclic Voltammetry (CV) and electron paramagnetic resonance (EPR) were used to characterize the autocatalytic system. The hydrogel obtained has excellent mechanical properties (strain >900 %, compressive strength >800 kPa, toughness >700 kJ/m³), reproducible adhesive properties (>10 times), excellent high and low temperature (-20-60 °C) adaptability and stability. And the excellent electrical conductivity endows the hydrogel with high strain sensitivity (GF = 5.15) over a wide strain range (400 %). The excellent overall performance ensures the stability and accuracy of the hydrogel as a flexible electronic skin for signal detection during human-computer interface interaction. This work contributes a new research strategy for the rational design and green development of biomass-based conductive hydrogel sensors.