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.