Covalent Organic Framework–Functionalized Polyurethane‐Based High‐Performance Stretchable and Breathable All‐Nanofibrous Triboelectric Nanogenerator for Wearable Sign Language Interpretation

Abstract Stretchability and breathability are crucial properties for wearable sensors, ensuring flexibility, user comfort, and reduced skin irritation. Herein, the fabrication of a polyurethane (PU)@1,3,5‐triformylphloroglucinol (Tp)–2,6‐diaminoanthraquinone (Dq)‐COF (PU@TpDq‐COF) composite nanofiber paired with a stretchable polyvinylidene fluoride–hexafluoropropylene@TPU (PVDF‐HFP@TPU) nanofiber is reported to develop a stretchable and breathable triboelectric nanogenerator (SB‐TENG)‐based sensor, enhancing wearability and user comfort while reducing the risk of skin inflammation. PU@TpDq‐COF serves as a positive tribomaterial, significantly enhancing its performance over PU. Investigation of its physical and triboelectric properties revealed that the incorporation of TpDq‐COF into PU enhances the dielectric properties, charge‐donating capability, and crystallinity, improving the triboelectric output. The fabricated SB‐TENG delivers an output of 1.06 kV with a power density of 9.95 W m −2 , which is 16‐fold higher than the pure PU nanofiber. It demonstrates excellent breathability (19.92 mg cm −2 h −1 ) and stretchability (60%), exceeding typical human sweat loss and skin strain capacity, making it a reliable power supply source and wearable self‐powered sensor. As a proof of concept, the SB‐TENG sensor is effectively integrated into various body parts and joints to monitor the activities of athletes and interpret sign language, demonstrating its potential for diverse human–machine interactions while ensuring excellent wearability, stretchability, and breathability.