Novel superhydrophobic NIR reflective coatings based on Montmorillonite/SiO2 composites for Energy-saving building

In recent years, cool building materials have received increasing attentions due to their superior energy-saving efficiencies. In this work, novel self-cleaning cool coatings based on fluorocarbon resin-montmorillonite (MMT)/SiO 2 composites were prepared for energy-saving buildings. The intercalation modification of MMT improved the dispersion stability of MMT in organic solvent. Surface modification of MMT and SiO 2 particles by fluoroalkyl silane (FAS) produced hydrophobic particles. Fluorocarbon resin was used as a binder. With the assistance of the micro/nano structure of montmorillonite/SiO 2 composites and low surface energy of FAS and fluorocarbon resin, superhydrophobic state of the MMT/SiO 2 composite coatings can be achieved. The maximum contact angle of the MMT/SiO 2 composite coatings was as high as 163.5°. The superhydrophobic composite coatings exhibited superior self-cleaning property and good mechanical durability. Furthermore, the NIR solar reflectance of the superhydrophobic montmorillonite/SiO 2 composite coatings ranged from 0.77 to 0.85. The composite coatings reduced the heat box’s inside temperature of by 5.9℃. Therefore, the integration of high NIR reflectance property and superior self-cleaning property makes montmorillonite/SiO 2 composite coatings good candidates as self-cleaning cool roof coatings for energy-saving buildings.