Self-healing, anti-freezing, and recyclable PAA/CMC/LS-EG hydrogel for durable flexible strain sensor and triboelectric nanogenerator

Conductive hydrogels possess excellent flexibility and tunable conductivity, making them promising materials for flexible strain sensor and triboelectric nanogenerator (TENG). However, conventional conductive hydrogels suffer from low mechanical strength, toxic crosslinkers, and poor recyclability. In this study, a lignosulfonate (LS)-Fe 3 + autocatalytic system was utilized to rapidly initiate the polymerization of polyacrylic acid (PAA). In addition, carboxymethyl cellulose (CMC) was incorporated to reinforce mechanical strength, while ethylene glycol (EG) was introduced to improve antifreezing and moisturizing properties. The resulting PCL-EG hydrogel was employed to fabricate flexible strain sensor and triboelectric nanogenerator. This hydrogel exhibits outstanding adhesion, self-healing ability, and recyclability. The PCL-EG hydrogel-based strain sensor exhibits a wide detection range and high sensitivity (GF = 13.3 at 300–500 % strain), enabling reliable monitoring of human motion across multiple body regions. Furthermore, TENG assembled with the PCL-EG hydrogel generate stable electrical output, sufficient to power small wearable electronics and support self-powered signal transmission. This work offers valuable insights and guidance for the development of multifunctional flexible electronic devices.