Ultrahigh moisture resistance, highly sensitive and flame retardancy wearable strain sensor for agile water rescue, fire alarm and human motion detection

Smart fabrics provide considerable inspiration for the construction of wearable electronic devices due to their excellent skin affinity and breathability. However, the limited tolerance to high humidity environments and the flammable nature of fabrics impedes broader practical applications. In this paper, by an advanced and effective method, phytic acid doped (PA-) polyaniline (PANI) was polymerized in-situ on cotton fabric deposited by carbon black (CB), and then modified by non-fluorine hydrophobic particles, a flexible breathable fabric-based strain sensor (HPCF) with ultrahigh moisture resistance, flame retardancy and environmental resistance was successfully prepared. The obtained sensor shows high sensitivity (16.14 kPa−1) in the detection range of 0–2 kPa, fast response/recovery time (82/40 ms) and high cycle stability (>10,000 cycles). Thanks to its excellent hydrophobicity (WCA = 153°) and flame retardancy properties, the material enables the detection of human movement (such as finger/wrist/elbow/knee/foot movement) under a variety of harsh conditions (extremely high temperatures, underwater, acid, alkali, salt and blown sand environments). More importantly, it can be further applied to remote detection of potentially dangerous scenarios. HPCF can successfully transmit the Morse code signals of “SOS” and “HELP” sent by drowning people, and realize water rescue. In case of fire, it serves as a fire warning sensor to realize agile (1 s) fire alarming. The highly sensitive and versatile HPCF fabric sensor enables physical condition monitoring for fire and rescue personnel working in high temperature and humidity environments, which is of great value for all human activities carried out in harsh environments.