Transparent hydrophobic thermal insulation CsxWO3-ZnO-SiO2 coatings:Energy saving, anti-dust and anti-fogging performance

Abstract

CsxWO3-ZnO-SiO2 smart coatings were proposed to achieve multiple functions, such as thermal insulation, anti-dust, anti-fogging and blocking harmful ultraviolet light, etc. The transparent hydrophobic hybrid resins were prepared from methyltriethoxysilane (MTES) and SiO2 sol, which was used as the substrate of the composite coating. The CsxWO3 is served as the near-infrared (NIR) absorber, and the ZnO is functioned as the ultraviolet (UV) blocking agent. Coatings with different ratios of CsxWO3 and ZnO were successfully prepared by co-blending with nano-SiO2 resin. The morphology, microstructure, surface composition, hydrophobicity, thermal stability, anti-dust and optical property of the composite coatings were investigated comprehensively. The transmittance of C10Z10 (CsxWO3 10%, ZnO 10%, nano-SiO2 resin 80%) coating at 370 nm is 2.3%, and the value of Solar Energy Transmittance Selectivity (SETS) is 0.665, which exhibits excellent NIR shielding ability. Compared with nano-SiO2 resin coating, the thermal insulation temperature difference can reach 7.0 °C. The C10Z10 coating showed good durability in the twenty times anti-dust repeated tests and the efficiency could maintain 70.3% after the repeating tests. The coating showed excellent sustainability after a 45-day outdoor exposure experiment and a 240 h of artificial accelerated aging experiment. Thus, the proposed CsxWO3-ZnO-SiO2 coatings are promising for outdoor smart windows.