High‐Sensitivity, Superhydrophobic, and Flame‐Retardant Wearable Flexible Sensor for Human Motion Monitoring and Underwater Signal Transmission

ABSTRACT Fabric‐based flexible piezoresistive sensors have garnered significant attention due to their potential applications in health monitoring and human‐machine interfaces. However, the inherent hydrophilicity and flammability of fabric‐based sensors limit their utility in extreme or harsh conditions. This study employs a concise and effective method to self‐assemble carbon black (CB) coated with chitosan (CS) and ammonium polyphosphate (APP) onto a fabric substrate, followed by surface modification via chemical vapor deposition of methyl trichlorosilane (MTS). The flexible fabric sensor with superhydrophobic and flame‐retardant properties was successfully prepared. The fabricated sensor exhibits high sensitivity (11.02 kPa −1 within the 0–5 kPa detection range), rapid response time (80 ms), and outstanding cyclic stability (>10 000 cycles). Its exceptional sensing performance enables reliable monitoring of human movements in various harsh environments. Specifically, the sensor effectively performs underwater monitoring tasks, successfully receiving Morse code signals transmitted by users to assist underwater rescue operations. This study provides new insights into the fabrication and application of superhydrophobic flame‐retardant flexible sensors.