Transparent,thermal insulation and UV-shielding coating for energy efficient glass window

Size-controllable double-shell hollow TiO₂@SiO₂ spheres (DHTSs) were fabricated using a simple sol-gel reaction. The size of DHTSs was controlled by using PS spheres with different size as templates. Moreover, DHTSs was also incorporated into waterborne polyurethane (WPU) matrix to prepare WPU/DHTSs composite film as glass coating. The effect of the diameter of DHTSs on the transparency, thermal insulation and UV-shielding properties of WPU/DHTSs composite film were investigated in detail. And the results revealed that the composite film with 230 nm-sized DHTSs exhibited the optimum performance. In addition, the temperature rise rate in the chamber fitted with the glass coated by WPU/DHTSs composite film (26%) was lower than that fitted with the common glass without coated by anything (48%). Therefore, the transparent coating with excellent thermal insulation and good UV-shielding properties will become a potential energy saving building glass coating.