Thermal properties of methyltrimethoxysilane aerogel thin films

Aerogels are light and porous solids whose properties, largely determined by their nanostructure, are useful in a wide range of applications, e.g., thermal insulation. In this work, as-deposited and thermally treated air-filled silica aerogel thin films synthesized using the sol-gel method were studied for their thermal properties using the 3-omega technique, at ambient conditions. The thermal conductivity and diffusivity were found to increase as the porosity of the aerogel decreased. Thermally treated films show a clear reduction in thermal conductivity compared with that of as-deposited films, likely due to an increase of porosity. The smallest thermal conductivity and diffusivity found for our aerogels were 0.019 W m(-1) K-1 and 9.8 x 10(-9) m(2) s(-1). Amodel was used to identify the components (solid, gaseous and radiative) of the total thermal conductivity of the aerogel. (C) 2016 Author(s).

Mots clés

silica aerogels; ambient-pressure; conductivity; reduction