Polyaniline/Sodium Chloride-enabled Electronic-Ionic Dual-Channel Conductive Hydrogel with High Toughness Based on Nanocellulose and Sodium Alginate for Wearable Strain Sensor

Traditional sensors suffer from poor flexibility, narrow strain range, and insufficient biocompatibility. To address these issues, this study developed a polyacrylamide/sodium alginate/betaine/cellulose nanocrystals/polyaniline-Na+ (PAM/SA/BA/CNCs/PANI-Na+) conductive hydrogel via one-pot in situ polymerization and ionic cross-linking. Acrylamide (AM) and SA served as monomers, CNCs as the filler, CaCl2 as the cross-linker, PANI and NaCl as conductive components, and BA as an antifreezing agent. The hydrogel exhibited a stress of 178.52 kPa, strain of 840.72%, and conductivity of 8.71 S m–1 (at 25 °C). It showed good fatigue resistance (dissipated energy ∼3.21 kJ m–3 after 10–100 cycles at 100% strain), antiswelling ability (swelling ratio 135% after 7 days), and stable performance at −40 °C. The hydrogel also inhibited both Gram-positive and Gram-negative bacteria. As a strain sensor, it achieved high sensitivity (gauge factor 3.03), fast response (283 ms), and rapid recovery (194 ms). This work provides a practical strategy for biobased conductive hydrogels in flexible sensing applications.