Hollow TiO_2 flake prepared from TiO_2 coated glass flake for solar heat protection and their thermal performance

摘要

Hollow TiO2 flake (HTFs) for use as a solar protectionmaterialwere prepared using TiO2 coated glass flake (TGF), followed by the etching of their core. Rutile TiO2, with high refractive index applied for solar heat protection, was densely and completely coated onto the glass flake (GF) surface using a titration method and a final shell thickness of 200-400 nmwas achieved. The solar reflectance of the TGF improved to 89% with increasing CIE lightness (L*). Furthermore, HTF with a hollowed out size of approximately 1-2 x 20 mu m were also obtained by etching their coreGFwith HF solution, resulting in a reduced thermal conductivity. The UV-Vis-NIR spectra, optical properties, and thermal conductivity of the hollowTiO(2) flakewas investigated to determine their solar heat protection capabilities. The HTF exhibits a higher solar reflectance (90%) and lower thermal conductivity (80mW/m.k) than solid GF and TGF. Hence, HTF is a suitable candidate for developing solar heat protection materials with a dual function. (C) 2018 Elsevier Ltd. All rights reserved.