Preparation and properties of self-cleaning F-SiO2/BaTiO3 coated cooling fabric
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 coated 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℃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 and outstanding mechanical strength,indicating broad application prospects in the outdoor scenario.
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