Passive radiation heating smart fabric with underwater sensor and electromagnetic wave absorption

Smart fabrics show a huge advantage in the field of flexible wearable electronics because of their superior hygienic properties. Here, a flexible wearable fabric for underwater sensing with both electromagnetic wave absorption (EWA) and passive radiation heating properties is fabricated by integrating polypyrrole (PPy), ferroferric oxide (Fe 3 O 4 ) nanospheres, and hydrophobic polyurethane (PDMS-PUF) onto the surface of the fabric. The multi-layer integrated structure allows the fabric sensor to be superhydrophobic (water contact angle is 154.5°) without much impact on its air permeability. At the same time, the conductive PPy network confers the fabric sensors with a rapid response rate (245/327 ms), effectively enabling long-term monitoring, especially during underwater sports in which the real-time altitude of the wearer can be monitored. Moreover, owing to the strong near-infrared absorption and ideal photothermal conversion performance of PPy, the fabric sensor achieves the maximum solar absorption rate (95.1 %) in the visible light region, and shows favorable radiative heating characteristics (10 min temperature rise of 23.5°C). Remarkably, the fabric is endowed with multiple loss mechanisms on the presence of PPy and Fe 3 O 4 , achieving prominent EWA properties (-29.1 dB at 12.16 GHz). Therefore, the smart fabric is an ideal candidate for smart swimsuits and health protection.