The Effect of Aging Process Conditions on Aerogel Performance

Aerogels are porous materials, largely composed of air, with bulk densities typically in the 0.01-0.1 g/cm3 range. The approximate values of the pore size are between 5 and 100nm, with BET surface area between 600 and 1000 m2. Porosity can be as high as 99% [1]. These materials were firstdescribed by Kistler, who reported their preparation from silica [2]. Aerogels could be ideal materials for commercial thermal and acoustic insulators, adsorbents, chromatographicpacking, or as hosts for a variety of functional guests for optical, electrical, and chemical applications [3]. Chemicalreactions that cause gelation continue long after the gel point during aging, producing strengthening, stiffening, and shrinkage of the network. This may result in the changes in thestructural and textural properties of the final aerogel product [4]. There is little information on the effect of aging on theporous texture of silica aerogels prepared by an accelerated gelation process using fluoride anion catalysts. In this work, a series of base-catalyzed silica aerogel samples were prepared using different aging conditions. Here we present how different aging conditions affect aerogels strength.