Characterization of mesoporous silica thin films for application to thermal isolation layer

Mesoporous silica thin films were easily prepared by a sol-gel process and spin-coating, and the film properties were investigated for potential application to thermal isolation layers. Scanning electron microscopy and X-ray diffraction were used to determine the film thicknesses and to analyze the mesoporous film structures, respectively. The refractive indexes and porosities of the films were determined by spectroscopic ellipsometry and the Lorentz-Lorenz equation, respectively. The infrared absorptions and thermal conductivities of the films were measured by Fourier transform infrared spectroscopy and a 3-ω method, respectively. The porosity and the number of pores of the films increased with increasing Brij-76 surfactant concentration, the interpore distance and thermal conductivity decreased. The experimental results showed that the mesoporous silica thin films could be function as excellent thermal isolation layers.