热致变色自适应辐射冷却涂层的制备及性能研究

Radiative cooling is a method of sustainable cooling without energy consumption, but the strong cooling effect will increase energy consumption of heating in cold winter, which is not conducive to energy saving and environmental protection. Therefore, a temperature-adaptive radiative cooling coating (TARCC, PM/TMHC) which consists of a radiative cooling underlayer based on a spectral selectivity porous polymer membrane (PM) and a thermochromic top layer based on thermochromic microcapsules hybrid coating (TMHC) was designed and fabricated in this paper. The color of the TMHC can be changed with the ambient temperature, and then the solar reflectance of the coating can be adjusted independently. The results show that the TMHC becomes transparent at high temperature, and the overall solar reflectance of PM/TMHC is 91.25 %, while the TMHC becomes rose red at low temperature and absorbs part of visible light, which can reduce the solar reflectance of PM/TMC to 72.71 %. In summer, when PM/TMHC is exposed to direct sunlight with an intensity of 900 W/m2, the backside temperature of the coating is 7.1 C lower than that of traditional colored coatings, and also lower than that of TARCC (CC/TMHC) with commercial white thermal insulation coatings (CC); in winter, when the solar intensity drops below 500 W/m2, the PM/TMHC keeps rose red and the backside temperature of it can be 6 C higher than that of the PM, achieving warm in winter and cool in summer. Moreover, the light fatigue resistance of the coating was significantly improved by using light stabilizer. The above work opened up a new way for intelligent building coatings, which has great development prospects.