Smart Thermochromic Nanofiber Membranes for Adaptive Thermal Management: Dynamic Switching between Radiative Cooling...

To address the increasing prevalence of extreme weather events, there has been a notable shift in research priorities toward the development of smart textiles capable of adaptively regulating the microclimate temperature of the human body. This study uses electrospinning technology to create multifunctional polyurethane nanofiber membranes (PUBPs) with a sandwich structure. The outer layer contains thermosensitive color-changing microcapsules (RT-BCMs) incorporated into the PU nanofiber membrane, and the middle layer contains phase-change microcapsules (RT-PCMs) incorporated into the PU nanofiber membrane. The PUBPs nanofiber membrane exhibits a reversible color change within a temperature range of 26-40 °C. At high temperatures, the membrane appears white, increasing solar reflectance to 87.4% while maintaining mid-infrared emissivity of 95.3%, thereby achieving radiative cooling. At low temperatures, the membrane appears blue, with solar reflectance reduced to 69.1% while maintaining mid-infrared emissivity of 95.1%, thereby achieving solar heating. The PUBPs nanofiber membrane is capable of acting as a temperature buffer zone, with a phase change enthalpy of up to 106.8 J/g. This property makes PUBPs nanofiber membrane effective in mitigating temperature fluctuations caused by external temperature changes. After 20 days of UV aging and 100 thermal cycles, optical property retention and phase-change performance remain essentially unchanged, showing great weather resistance ability and cycling stability. Outdoor experiments show that under low solar irradiance of 163.2 W/m², the maximum temperature rise is 5.4 °C; under high solar irradiance of 958.2 W/m², the maximum temperature drop reaches 8.8 °C. This PUBPs nanofiber membrane, prepared through the synergistic mechanism of thermochromic and phase-change functions, effectively achieves all-season adaptive thermal management and provides a strategy for developing smart, temperature-controlled textiles.