Ultrasensitive, highly stretchable, self-healing and robust quaternized chitosan-based conductive hydrogel for wearable sensors.

Conductive hydrogels are widely used in electronic skin and wearable sensors. Their inherent self-adhesion, exceptional sensitivity, and remarkable toughness guarantee the consistent and reliable operation of flexible motion sensors. However, creating chitosan-based conductive hydrogels with all these properties remains challenging. In this study, a triple-network hydrogel was synthesized by incorporating poly (vinyl alcohol) (PVA), chitosan quaternary ammonium salt (QCS) and poly(N-(2-Hydroxyethyl) acrylamide)-Co-Sodium acrylate copolymer (P(HEAA-Co-AANa)). Lithium chloride (LiCl) is introduced to enhance conductivity. The optimized hydrogel shows good conductivity (0.77 S/m), high tensile strain (~2113 %) and strong mechanical properties (463 kPa). The assembled sensors have high sensitivity, and enable precisely monitoring human motions. This study offers a simple, eco-friendly way to develop high-performance chitosan-based conductive hydrogels.