A Real-Time Solar UVA Dose Monitor Based on Recyclable Azobenzene-Containing Elastomer Fabrics

Solar ultraviolet (UV) radiation, a primary cause of skin cancer and erythema, poses irreversible risks to human health, underscoring the urgent need for advanced solar UV detector. Herein, we present a novel intrinsically flexible UVA detector featuring real-time monitoring, high performance and recyclability. This breakthrough is achieved through engineered oriented composite fabrics combining main-chain azobenzene-thermoplastic polyurethane elastomers (Az-TPU) with piezoelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] nanogenerators. The molecular architecture employs azobenzene groups and 4,4'-methylene diphenyl diisocyanate (MDI) as hard segment, while polytetramethylene ether glycol (PTMG) forms the soft segment. The physical cross-linking network and homogeneous microphase-separated structure enables the fabrics to generate substantial internal stress, resulting in superior photoelectrical conversion capabilities. The device we report achieves an 80 ms response time and maintains excellent linear correlation (R² = 0.997) across a broad light intensity range (0.05-50 mW·cm^-2). Remarkably, the fabric achieves dynamic UV light monitoring when subjected to a tensile strain of 10%. Integrated with Bluetooth communication, the device enables real-time data transmission to mobile devices for continuous UVA intensity and dose monitoring throughout daily sunlight exposure. With demonstrated capability for solar UVA measurement, this technology presents significant industrial potential for wearable solar UV monitoring systems.