A SYNTHETIC ROUTE TO ORGANIC AEROGELS - MECHANISM, STRUCTURE, AND PROPERTIES

The base catalyzed, aqueous reaction of resorcinol with formaldehyde follows a sol-gel pathway in which surface functionalized polymerclusters are formed. The covalent crosslinking of these clusters produces gels which are dried under supercritical conditions to obtain low density, organic aerogels (≤ 200 mg/cc) . The aerogels are transparent and have cell sizes less than 100A. Their microstructure consists of interconnected colloidal-like particles with diameters of 30-100 A. The particle size, cell size, surface area, and density of resorcinol - formaldehyde (RF) aerogels are largely determined by the catalyst concentration in the mixture. RF aerogels are similar to silica aerogels in many ways, yet a comparison of their mechanical properties suggests subtle morphological differences.