Study on the thermal stability of ordered mesoporous SiO ₂ film for thermal insulating film

Ordered mesoporous SiO ₂ film has very low thermal conductivity compared to dense SiO ₂ film due to the presence of nanometer-sized pores. In order to apply this excellent material to thermal insulation fields, it is important to ensure the thermal stability of the pore structure at high temperature as well as thermal conductivity. In this study, ordered mesoporous SiO ₂ films were synthesized with various amounts of surfactant, and heat treatment at various temperatures was conducted with the synthesized films to confirm their thermal stabilities. Pore structure degradation of the mesoporous SiO ₂ film was observed with increasing temperature of the heat treatment as measured by grazing incidence small angle X-ray scattering. However, mesoporous SiO ₂ films with highly-ordered pore arrangements showed enhanced thermal stability and maintained their pore structures during additional heat treatment at higher temperatures. The mechanical properties and thermal conductivity of the ordered mesoporous SiO ₂ films with thermal stability at high temperature were analyzed.