Hollow TiO2 flake prepared from TiO2 coated glass flake for solar heat protection and their thermal performance

Publication date: 15 July 2018
Source:Materials & Design, Volume 150
Author(s): Hee Jung Kim, Hyun Jin Lee, Dae-Sung Kim
Hollow TiO2 flake (HTFs) for use as a solar protection material were 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 nm was 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 × 20 μm were also obtained by etching their core GF with HF solution, resulting in a reduced thermal conductivity. The UV–Vis-NIR spectra, optical properties, and thermal conductivity of the hollow TiO2 flake was investigated to determine their solar heat protection capabilities. The HTF exhibits a higher solar reflectance (90%) and lower thermal conductivity (80 mW/m·k) than solid GF and TGF. Hence, HTF is a suitable candidate for developing solar heat protection materials with a dual function.

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