聚偏氟乙烯多孔涂层织物的制备及其日间被动辐射制冷性能OA

Overheating is closely linked to life safety,environmental issues,etc.It not only endangers human health,but also speeds up the melting of Earth's glaciers,thereby exacerbating socio-environmental problems such as extreme weather events and challenges to animal survival.Traditional cooling methods often involve energy dissipation as well as the consumption of water or chemicals.In contrast,passive daytime radiative cooling(PDRC),as an efficient and energy-free cooling approach,can handle overheating problems without consuming energy,thus holding broad application prospects in fields like energy-efficient buildings,automobiles,batteries,and personal thermal management.Currently,there are still many problems in the research and application of PDRC textiles.For instance,issues such as the large amount of inorganic particles required,the poor flexibility of coated textiles,the easy peeling-off of coatings,and the complexity of the fabrication process persist. The preparation of PDRC-coated textiles with both flexibility and multifunctionality remains challenging.In this study,polyvinylidene fluoride(PVDF)porous coated fabrics were prepared by solvent-nonsolvent induced phase separation method using cotton fabric as the substrate and PVDF as the coating matrix material.A systematic investigation was conducted to analyze the effects of the PVDF-to-DMF ratio and coating thickness on the microstructure and optical properties of the coating.The radiative cooling performance was evaluated through cooling experiments,while the hydrophobic self-cleaning performance was assessed via water contact angle measurements and anti-fouling tests.Finally,the relationships between the microstructure of the PVDF porous coating and its radiative cooling performance,as well as its hydrophobic self-cleaning properties,were established.The experimental results show that when the mass ratio of PVDF to DMF is 1∶5 and the coating thickness is 300 μm,the coated fabric has a relatively uniform micro-nano rough and porous structure,which enables effective scattering and reflection of sunlight.And the PVDF porous coated fabric demonstrates a high solar reflectance of 0.91 and a high thermal emissivity of 0.95.In daytime continuous cooling tests against human skin,it achieves a sub-ambient cooling effect of 19.3℃,effectively preventing skin overheating by 1.2℃.In addition,the coated fabric has a high hydrophobic contact angle of approximately 144.6° and good self-cleaning performance.After 200 cycles of abrasion,it still retains its hydrophobicity and high reflectance,indicating good durability. In recent years,with the emergence of advanced design and manufacturing technologies,new types of selective infrared radiators,including photonic structures and metamaterials,have been rapidly developed.Given the diversification of application scenarios and demands today,the research and development of multifunctional radiative cooling materials hold significant importance for enhancing the application and promotion of radiative cooling materials.