Control of mesoporous structure of aerogels derived from cresol-formaldehyde

Polycondensation of a cresol mixture (C-m) with formaldehyde (F) in basic aqueous solutions leads to formation of highly cross-linked CmF aquagels that can be supercritically dried with carbon dioxide to form organic CmF aerogels. Aerogels synthesized with different catalyst contents and reactant concentrations are characterize by low-temperature nitrogen adsorption. The present experimental results suggest that the CmF aerogels are typical mesoporous materials and have almost no micropores in bulk. The microstructure of the organic CmF aerogels can be controlled and tailored effectively by varying synthesis conditions during the initial sol-gel process. CmF organic aerogels with specific surface area as high as 627 m(2)/g and corresponding pore volume 2.06 ml/g have been obtained with a dominant pore size of 30 nm. CmF organic aerogels with peaky pore size distributions concentrated at 11 run have also been prepared. (C) 2002 Elsevier Science (USA).