Abstract: Abstract By using the microwave-assisted method, the size and morphology of zirconium-based metal-organic frameworks(UiO-66) were precisely controlled to prepare UiO-66 nanocrystals with high scattering efficiency. Employing these as high-infrared-emissivity functional materials, a UiO-66-functionalized polylactic acid (PLA) porous fiber membrane was further constructed via electrospinning-spraying technology combined with a phase separation strategy. Benefiting from the micro-nano porous design and the introduction of abundant infrared-active groups from UiO-66, the PLA/UiO-66 porous fiber membrane exhibited excellent solar reflectivity and infrared emissivity. Particularly when the UiO-66 addition amount was 12%, the optical performance of the resulting PLA/UiO-66-12 porous fiber membrane was even more outstanding, achieving an average solar reflectivity of 93.9% and an average infrared emissivity of 91.2%, far exceeding those of the pure PLA fiber membrane. In outdoor tests, the cooling effect of the PLA/UiO-66-12 porous fiber membrane was significantly superior to that of the pure PLA fiber membrane. The average temperature of PLA/UiO-66-12 remained at 47.6 °C, whereas the average temperature of the pure PLA fiber membrane was above 50 °C. While demonstrating excellent cooling performance, the incorporation of UiO-66 effectively reduced the surface energy, endowing the PLA/UiO-66 porous fiber membrane with a high water contact angle(128.8°). This ensures the membrane possesses outstanding hydrophobicity and self-cleaning capability, thereby providing a new strategy for developing efficient and sustainable thermal management textiles.

Key words: Poly(lactic acid), Radiative cooling, Porous fiber, Metal-organic framework material; Self-cleaning property