Characterization of silica-based aerogels: Surface area, pore size distribution and infrared spectra

CHED 1373

Adam E. Reeve1, Mary K. Carroll, carrollm@union.edu1, David C. Korim2, and Ann M. Anderson, andersoa@union.edu2. (1) Department of Chemistry, Union College, Schenectady, NY 12308, (2) Department of Mechanical Engineering, Union College, Schenectady, NY 12308
Our group prepares silica aerogels using two methods: the Union College Rapid Supercritical Extraction (RSCE) method, which employs a hot press, and a more conventional auto-clave-based technique. We have undertaken measurements of surface area and pore size distribution, and collected infrared spectra of a variety of aerogel samples. Our goals are to ascertain whether materials prepared by these two methods differ significantly, and to evaluate whether mechanical testing affects the aerogel materials. Aerogels were prepared from a precursor mixture of TMOS, methanol, and water, with ammonia as the catalyst. RSCE aerogels have average pore diameters of 5 to 20 angstroms, surface areas greater than 500 m2/g, and IR spectra consistent with an overall SiO2 structure. We will also present a comparison of pore sizes among aerogels that have been crushed, chopped, or compression tested – processes that might lead to pore collapse within the aerogel – to unaltered aerogels.