Dioxybenzene-bridged hydrophobic silica aerogels with enhanced textural and mechanical properties

Abstract

Designing aerogel materials with excellent mechanical robustness while maintaining their basic characteristics, is of great importance for applications in energy saving management systems. Organic modification is required to strengthen silica aerogel, but the modified aerogels show decreased textural properties due to phase separation between organic-inorganic components. We report, the fabrication of organically modified aerogels without minimizing their basic properties, based on tetraethoxysilane (TEOS) and a bifunctional precursor prepared from dihydroxybenzene and TEOS via acid catalyst. Three types of dihydroxybenzene isomers were used to study the effect of the position of the hydroxyl groups on textural properties of aerogels and compatibility of the precursors. A simple, efficient, and cost effective sol-gel method was employed to develop porous aerogels with no additives and surfactants. Hydroquinone-TEOS (HT) bridged silica aerogels exhibited improved mechanical strength, low dipole moment, high specific surface area (1154 m(2)/g), high porosity (96%), low density (0.061 g/cm(3)), and ultra-low thermal conductivity of 0.0334 W/m.K. In addition, precursor was cheaper than the other isomers. The prepared aerogels show hydrophobic nature without the use of harmful silylating reagents.