Ultrastretchable, Antifreeze, Self-Healing, Conductive Hydrogel-Based Triboelectric Nanogenerators for Human Motion Detection and Signal Transmission

Wearable electronic devices based on conductive hydrogels have gained attention for applications in health monitoring, electronic skin, and human–computer interaction. However, limited functionality hinders the development of conventional hydrogels. Herein, a multifunctional poly(acrylic acid)/carboxymethyl cellulose/polydopamine-ethylene glycol (PAA/CMC/PDA-EG) hydrogel is developed via free radical polymerization initiated by a PDA-Fe³⁺ redox system and dynamic metal coordination. The hydrogel exhibits excellent mechanical properties (tensile strength, 71 kPa; elongation, 872%), strong adhesion, self-healing ability, and environmental tolerance (nonfreezing at −15 °C). It functions as a strain sensor with a wide working range (0–500%) and high sensitivity (GF = 10.49), suitable for human motion detection. As an electrode in a triboelectric nanogenerator (TENG), the hydrogel delivers stable electrical output (open-circuit voltage: 100 V), powering small electronics and enabling signal transmission. This work provides a reference for the development of multifunctional hydrogel-based flexible electronics and self-powered devices.