Brittle Star-Inspired Composites With Excellent Tribopositivity, Tensile Properties, and Self-Healing Capability for Self-Powered Flexible Sensors.

Abstract

Self-powered sensing devices for human-machine interaction suffer from poor mechanical robustness, fragile structural stability, and fluctuating sensing signals under cyclic deformation, severely restricting their long-term operational reliability. Integrating self-healing functionality into triboelectric substrates is an effective approach to address these bottlenecks, but it remains challenging to simultaneously realize superior stretchability, steady electrical output, and efficient self-healing performance in a single material system. Inspired by the arm structure of brittle stars, a waterborne polyurethane (WPU) incorporating dynamic disulfide and hydrogen bonds was fabricated, and the hydrogen-bonding interfacial network between MXene and WPU was tailored. A composite system enabling synergistic multilevel energy dissipation through reversible dynamic bonds and disulfide exchange was therefore constructed. The resulting MXene/WPU (M-WPU) composite film exhibits a tensile strength of 14.7 MPa, an elongation at break of 970%, a triboelectric output of 14 µA, and a self-healing efficiency of 89% after thermal healing at 100°C for 12 h. The flexible sensor assembled from this M-WPU film, integrated with machine learning, enables accurate handwriting recognition and human-machine interaction. Notably, after macroscopic crack self-healing, the M-WPU can still maintain stable electrical signal output, offering novel design insights for the development of long-life, highly reliable self-powered flexible sensors.