Preparation and Properties of TiO2-Coated Hollow Glass Microspheres as Thermal Insulation Materials for Energy-Saving Buildings

A hollow glass microsphere(HGM)/TiOcomposite hollow sphere was successfully prepared via a simple precipitation method. The TiOcoating layers grew on the surface of the HGMs that range from 20 to 50 μm in diameter as nanoparticles with the formation of the SiO Ti bonds. The growth mechanism accounting for the formation of the TiOnanolayers was proposed. The morphology, composition, thermal insulation properties, and visible–near infrared(VIS–NIR) refl ectance of the HGMs/TiOcomposite hollow spheres were characterized. The VIS–NIR refl ectance of the HGMs/TiOcomposite hollow spheres increased by more than 30% compared to raw HGMs. The thermal conductivity of the particles is 0.058 W/(m K). The result indicates that the VIS–NIR refl ectance of the composite hollow spheres is strongly infl uenced by the coating of TiO. The composite hollow spheres were used as the main functional fi ller to prepare the organic–inorganic composite coatings. The glass substrates coated by the organic–inorganic coatings had lower thermal conductivity and higher near infrared refl ectivity. Therefore, the HGMs/TiOcomposite hollow spheres can refl ect most of the solar energy and eff ectively keep out the heat as a thermal insulation coating for energy-saving constructions.