Abstract: Global warming and urban heat island effect have a significant influence on social progress and survival of human beings. Excessive heat in outdoor space can reduce the lifespan of outdoor products and pose a threat to people's safety. Therefore, during hot summer days, outdoor protective equipment with cooling functions has become increasingly popular. Passive daytime radiative cooling (PDRC) technology is an effective strategy for achieving outdoor cooling. It can cool the surface of the subject solely through the inherent properties of the material itself without consuming any energy. PDRC materials reflect sunlight with wavelengths ranging from 0.3 to 2.5 µm and radiate heat through the atmospheric window (8–13 µm) into outer space. Combining radiative cooling technology with textiles to prepare cooling textiles is meaningful. 
However, it is difficult to achieve high cooling performance while maintaining good usability of textiles. Meanwhile, outdoor cooling textiles inevitably encounter rainfall and atmospheric sediments during use. These contaminants will accumulate on the surface of textiles, reducing their sunlight reflectance and infrared emissivity, which in turn affects the cooling performance. Therefore, it is necessary to develop PDRC textiles that have anti-contamination capabilities and can continuously achieve high-efficiency cooling effect. In this study, PDMS and fluorosilane-modified SiO2 particles were used to combine with visible-near infrared highly reflective BaTiO3 particles to prepare PDRC coating with self-cleaning property on nylon fabrics to obtain coating fabrics with cooling effect. The morphology and chemical structure of the coated nylon fabrics were analyzed. The influencing factors of the spectral characteristics of the coated nylon fabric were studied. The cooling performance, self-cleaning performance, and mechanical properties of fabrics were also investigated.
 The results show that the coated fabric has a comparatively higher sunlight reflectance and mid-infrared emissivity, and both the sunlight reflectance and mid-infrared emissivity increase with the increase of coating amount. When the coating amount is 8.59 mg/cm2, the average sunlight reflectance of the coated fabric is 88%, and the average mid-infrared emissivity is 92%. Compared with the original nylon fabric, the coated fabric can reduce the temperature by up to 5.6 °C when the solar radiation intensity is 558 W/m2. Meanwhile, the composite coated fabric has a hydrophobic surface with a water contact angle of 146.6°, and it possesses excellent cooling performance, self-cleaning ability, abrasion resistance and outstanding mechanical strength, indicating broad application prospects in the outdoor scenario.

Key words: radiative cooling, SiO2, BaTiO3, coating, nylon, self-cleaning

摘要： 为了制备具有自清洁功能的降温织物，选用锦纶牛津布为基材，使用氟硅烷改性二氧化硅粒子，将聚二甲基硅氧烷(PDMS)、含氟烷基改性二氧化硅(F-SiO2)、钛酸钡(BaTiO3)通过刮涂的方式整理到锦纶织物上，获得复合降温涂层织物；对所得织物的微观结构和表面化学组成进行测试，探究不同涂覆量对复合涂层织物太阳光反射率和中红外发射率的影响，评估涂层织物的降温性能、易去污性能、机械性能。结果表明：复合涂层的引入能显著提高织物的光谱性能，与原始锦纶相比，制备的复合涂层织物的太阳光反射率提高至88%，大气窗口红外发射率可达92%。在户外太阳直射的情况下，制备的复合涂层织物相比原始锦纶织物最高可降温5.6 ℃，且具有很好的自清洁易去污效果和机械性能，在户外装备降温、电器设备降温、建筑路面降温等领域具有广泛的应用前景。

关键词: 辐射降温, SiO2, BaTiO3, 涂层, 锦纶, 自清洁