Mao Junxia, Tan Xinyu, Hu Weiwei, Shi Chao, Zhou Fan, Tsamis Alkiviadis
College of Materials and Chemical Engineering, Hubei Provincial Engineering Research Center for Solar Energy High-value Utilization and Green Conversion, China Three Gorges University, Hubei Provincial Yichang China
College of Electrical Engineering & New Energy, Hubei Provincial Collaborative Innovation Center for New Energy Microgrid, China Three Gorges University, 8 University Avenue Yichang 443002 PR China.
RSC Adv. 2024 Nov 18;14(49):36656-36666. doi: 10.1039/d4ra06819j. eCollection 2024 Nov 11.
Daytime radiative cooling is a technique that relies on reflecting sunlight and radiating heat through mid-infrared wavelengths to cool objects. However, most daytime radiative cooling materials are not transparent, cannot be used for vehicle windows or other objects that need to retain their original color, and are susceptible to rain, dust, and other contamination, resulting in reduced cooling performance. Here, we developed a transparent, self-cleaning, radiative cooling, highly flexible PVDF composite film (PPF film), which was prepared by solvent evaporation phase conversion method and scraping coating method. The preparation method is simple and the material is easy to obtain. The obtained PPF film can be crimped to different degrees, has high flexibility, a transmittance of 94% in the visible light range (380-760 nm), and a water contact angle of 105° and above, and has self-cleaning performance. In the range of 8-13 μm, the average emissivity of the film reached 94.42%. Outdoor experiments show that, on sunny days, the cavity temperature of the device coated with PPF film glass decreases by 5-6 °C compared with that of bare glass, indicating that the PPF film has excellent radiative cooling performance. In addition, it has relatively strong mechanical properties, ultraviolet aging resistance and acid and alkali resistance. The design of the PPF film enables the radiative cooling material to be transparent, self-cleaning and flexible, with broad application prospects in the outer surface of objects requiring light transmission and cooling, such as special-shaped curved surfaces, solar panels, and architectural glass.
日间辐射制冷是一种通过反射阳光并通过中红外波长辐射热量来冷却物体的技术。然而，大多数日间辐射制冷材料不透明，不能用于车窗或其他需要保持原有颜色的物体，并且易受雨水、灰尘和其他污染物的影响，导致制冷性能下降。在此，我们开发了一种透明、自清洁、辐射制冷、高柔韧性的聚偏氟乙烯复合薄膜（PPF薄膜），它是通过溶剂蒸发相转化法和刮涂法制备的。制备方法简单，材料易于获得。所得到的PPF薄膜可以进行不同程度的卷曲，具有高柔韧性，在可见光范围（380 - 760nm）内的透光率为94%，水接触角为105°及以上，并且具有自清洁性能。在8 - 13μm范围内，该薄膜的平均发射率达到94.42%。户外实验表明，在晴天，涂覆有PPF薄膜玻璃的装置的腔体温度比裸玻璃降低了5 - 6°C，这表明PPF薄膜具有优异的辐射制冷性能。此外，它具有相对较强的机械性能、抗紫外线老化性能和耐酸碱性能。PPF薄膜的设计使辐射制冷材料具有透明、自清洁和柔韧性，在需要透光和冷却的物体外表面，如异形曲面、太阳能电池板和建筑玻璃等方面具有广阔的应用前景。
