Highly Integrated Phase Change and Radiative Cooling Fiber Membrane for Adaptive Personal Thermal Regulation

Abstract Environmental heat influx often limits the effectiveness of radiative cooling materials, particularly in wearable applications where thermal comfort is paramount. This study introduces an innovative solution for personal thermal management through radiative cooling phase change (RC‐PC) fiber membranes. Fabricated by coaxial electrospinning, these membranes combine a poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) and tetraethyl orthosilicate (TEOS) composite shell, encapsulating n ‐octadecane as the core phase change material. The membranes demonstrate exceptional optical performance, with a solar reflectivity of 95.0% and an emissivity of 88.6% within the atmospheric window, effectively minimizing ambient heat absorption. The n ‐octadecane‐infused fibers (0.3 mL h −1 C18@TEOS/PHBV) exhibit a phase change enthalpy of 88.3 J g −1 , reducing heating rates and improving cooling by ≈1 °C at dawn. Under typical solar radiation (939.5 W m −2 ), the membranes provide an average cooling power of 89.0 W m −2 , peaking at 95.3 W m −2 . Notably, they achieve a cooling reduction of 5.1 °C under 550.2 W m −2 , maintaining temperatures significantly lower than conventional fabrics, with a differential of 4.4 °C compared to medical protective clothing. These findings underscore the potential of RC‐PC fiber membranes for sustainable, efficient personal thermal management.