Abstract: This pertains to the general field of gels, foams, and aerogels, particularly, to low density open cell organic foams and low density open cell carbon foams, and methods for preparing them. These low density open cell organic foams are derived from organic gels which may be prepared from hydroxylated benzenes (such as phenol, catechol, resorcinol, hydroquinone, and phloroglucinol) and aldehydes (such as formaldehyde and furfural) using lower than conventional catalyst concentrations (e.g, an R/C value of greater than about 1000, yielding an initial room temperature pH typically lower than about 6.0). These organic foams are characterized by relatively large particle and pore sizes, high porosity, and high surface area. Low density open cell carbon foams derived from such organic foams are also shown, as are methods for preparing same. These carbon foams are also characterized by relatively large particle and pore sizes, high porosity, high surface area, and high electrical capacitance.

Abstract: Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels.