Preserving spectral selectivity of radiative cooling textile under sweating conditions in hot urban environments.

Atmospheric window (8-13 μm) spectrally selective radiative-cooling textiles can minimize heat gain from the surroundings, especially under the urban heat-island conditions. However, perspiration can substantially degrade this selectivity because sweat has broadband emissive properties. Here, we design an integrated spectrally selective radiative cooling textile with directional sweating capability. Embedded conical microstructures drive rapid sweat transport and shedding, maintaining a dry radiative surface and thereby preserving spectral selectivity. By incorporating 20 wt% silicon nitride particles into polyvinyl butyral fibers, the textile achieves 83.8% emissivity within atmospheric window, 43.3% emissivity within non-atmospheric window (2.5-8 µm and 13-20 µm), and 92.8% solar reflectivity. After sweating, it still possesses 84.4% atmospheric-window emissivity and 45.4% non-atmospheric window emissivity, demonstrating robust spectral preserving capabilities. Outdoor experiments demonstrate that the spectrally selective textile is 2.8 °C and 7.3 °C cooler than broadband textile and cotton, respectively, highlighting its potential for personal radiative cooling in hot urban environments.