纯水体系SiO2纳米多孔材料的低成本制备与表征

A Low-cost Preparation of SiO_2 Aerogel Monoliths from Silica Sol

以低成本工业级硅溶胶为硅源,水为溶剂,在常压条件下干燥后制备出纳米多孔Si O2块体材料。在制备过程中,采用表面活性剂十六烷基三甲基溴化铵（CTAB）来降低水的表面张力,减少样品在干燥过程中开裂和收缩,避免了繁琐的溶剂替换过程。所制备的Si O2块体密度为150～260 mg/cm^3,比表面积为91～140 m^2/g,平均孔径为15～27 nm,其室温热导率可达0.048 W/（m·K）。该方法大大缩减了制备Si O2纳米多孔材料的成本,并降低了操作工艺难度和危险,将在很大程度上推动硅纳米孔材料的工业化生产与应用。

Porous monolithic Si O2 materials were prepared via ambient pressure drying process with low cost silica sol as precursor and water as solvent. Cetyl trimethyl ammonium bromide（CTAB） was used as the surface modifier to get rid of the cumbersome process of solvent substitution which was necessary in the traditional ambient drying process. The densities, specific surface area and the average pore size of the obtained Si O2 monoliths are in the range of 150–260 mg/cm^3, 91–140 m^2/g and 15–27 nm, respectively. The thermal conductivity was as low as 0.048 W/（m·K） at room temperature. This method greatly reduced the preparation cost as well as the operation difficulty and risk, which will largely promote the industrial production and application of porous Si O2 materials.