Controllability of pore characteristics of resorcinol-formaldehyde carbon aerogel

Resorcinol-formaldehyde (RF) aerogels were synthesized by sol-gel polycondensation of resorcinol with formaldehyde in a slightly basic aqueous solution, followed by drying with supercritical carbon dioxide. The RF carbon aerogels were prepared by carbonizing the RF aerogels at a high temperature under a nitrogen atmosphere. On changing the catalyst species and the catalyst ratios in synthesizing the RF hydrogels, we investigated their influence on the pore characteristics of the RF carbon aerogels prepared. We found that the order in the magnitude of the peak radii in the size distributions agrees with that in the magnitude of the gyratory radius measured from the small-angle X-ray scattering curves of the RF solutions during their gelation process. The gyratory radii and the form of the primary particles constituting the RF hydrogel were found to determine the pore characteristics of aerogels, relating to the polymerization conditions such as the catalyst species and the catalyst ratios in synthesizing the RF hydrogel. (C) 2004 Elsevier Ltd. All rights reserved.