Significance Passive radiative cooling (PRC) is a technology that achieves energy-free temperature reduction by radiating waste heat to the low-temperature universe through the 8-13 μm atmospheric transparent window. It has been widely applied in fields such as energy-saving buildings, photovoltaic cooling, and food preservation. In recent years, global warming has driven an urgent demand for the development of cooling garments. Currently, the mainstream design strategies for cooling garments include air cooling, liquid cooling, and phase change, but all suffer from defects such as complex systems and poor wearability. Based on Mie scattering theory, the use of fibers or particles with sizes comparable to light wavelengths can block solar thermal input, and the construction of radiative heat transfer channels by regulating mid-infrared emissivity in the 8-13 μm band enables spontaneous human body cooling. This strategy balances cooling efficiency and energy consumption but requires a trade-off among fabric spectral properties, mechanical performance, and wear comfort. By reviewing the cooling mechanism of PRC materials and their research and application status in fabrics, this paper provided theoretical and practical references for the development of PRC cooling garments.

Analysis/Progress Based on the analysis of the cooling mechanism of PRC fabrics, their cooling effect depends on the surface radiative properties of materials, with the core influencing indicators being mid-infrared emissivity (ε) and solar reflectivity (ρ_λ). Both can be improved through material structure regulation and component optimization. Mid-infrared emissivity can be enhanced by constructing surface microstructures and selecting materials with functional groups matching the atmospheric window. Solar reflectivity can be optimized by constructing porous or layered structures and incorporating high-refractive-index fillers. Currently, the core research paths of PRC fabrics are divided into two categories. The first approach is the porous structure construction, where porous fabrics (e.g., nanoPE and CA fabrics) are prepared through processes like bionic natural fibers, electrospinning, and solvent evaporation. This method can achieve significant cooling effects, but it faces problems such as high preparation difficulty, electrospinning's high energy consumption and low productivity. The second approach involves the modification of material coatings, including ordinary nanoparticle coatings, CA-based composite coatings, Janus structure coatings, and dynamic infrared regulation coatings, which can realize cooling, bidirectional thermal regulation, and local thermal management functions (e.g., PET-CA-MgO fabrics and carbon nanotube thin-layer dynamic fabrics). However, these coatings have defects such as uneven dispersion of nano-fillers and complex dynamic regulation processes. Phased progress has been made in various technologies, laying a foundation for the practical application of PRC fabrics.

Conclusion/Prospect With the advantages of energy-free operation and efficient cooling, PRC fabrics have become ideal materials for cooling garments. On the basis of research on cooling performance, preliminary technological breakthroughs in bidirectional thermal regulation and wearable local thermal management have been achieved. The two core paths of porous structure construction and material coating modification provide effective support for performance improvement. However, restricted by processing technologies, PRC fabrics still face bottlenecks such as electrospinning's high energy consumption and low productivity, poor uniformity of nano-filler dispersion, and complex dynamic radiative regulation processes, and have not yet achieved industrial application. In the future, efforts should be focused on optimizing large-scale and low-cost preparation processes, while breaking through technical difficulties in filler dispersion and dynamic regulation. Future research should further promote the application of bidirectional function integration and dynamic precise regulation technologies in PRC fabrics, in order to achieve a balance among cooling performance, mechanical properties, and wear comfort. Such progress will accelerate the industrialization of PRC fabrics in cooling garments and wearable local thermal management fields, providing better solutions for energy-saving cooling and human thermal comfort guarantee.