Resorcinol-formaldehyde (RF) cryogels were synthesized by sol-gel polyconde
nsation of resorcinol with formaldehyde and freeze drying with t-butanol. T
he cryogels were characterized by nitrogen adsorption and density measureme
nts. Their porous properties were compared with those of RF aerogels prepar
ed by supercritical drying with carbon dioxide. RF cryogels were mesoporous
materials with large mesopore volumes >0.58 cm(3)/g. Although surface area
s and mesopore volumes of the cryogels were smaller than those of the aerog
els, the cryogels were useful precursors of mesoporous carbons. Carbon cryo
gels were obtained by pyrolyzing RF cryogels in an inert atmosphere. Carbon
cryogels were mesoporous materials with high surface areas >800 m(2)/g and
large mesopore volumes >0.55 cm(3)/g. When pyrolyzed, micropores are forme
d inside the cryogels more easily than inside the aerogels. (C) 1999 Elsevi
er Science Ltd. All rights reserved.