A novel silica nanowire-silica composite aerogels dried at ambient pressure

Abstract

A novel silica nanowire-silica composite aerogels with excellent thermal insulation and mechanical properties was prepared by adding SiO2 nanowires as a secondary phase into the silica matrix and drying at ambient pressure. The SiO2 nanowires and silica aerogel matrix have outstanding compatibility and dispersibility because the components of nanowire and aerogel matrix all are silica, which contributes to the improvement of the mechanical property of the silica composite aerogels. The physical, mechanical and thermal properties of the SiO2 nanowires based composite silica aerogel are investigated and discussed in detail. The results indicate that the monolithic aerogels with high specific surface area, porosity and large pore volume. The thermal conductivity of the composite silica aerogels only increases gently (0.006W·m−1K−1) as the addition of SiO2 nanowires rises from 0wt% to 14wt%, while their mechanical properties have been improved greatly. The SiO2 nanowires based composite silica aerogel would be widely used in the thermal insulation application because of its outstanding thermal insulation property.