Pore structure evolution in silica gel during aging/drying. III. Effects of surface tension

A two-step acid/base-catalyzed silica gel has been aged in alcohol and water baths followed by various aprotic solvents with a wide range of surface tensions. Low temperature (CO 2) and high temperature (ethanol) aerogels were also prepared. The physical and chemical structures of gels dried from ap...

Full description

Saved in:
Bibliographic Details
Published in:Journal of non-crystalline solids 1992, Vol.144 (1), p.32-44
Main Authors: Deshpande, Ravindra, Hua, Duen-Wu, Smith, Douglas M., Brinker, C. Jeffrey
Format: Article
Language:English
Subjects:
Chemistry
Colloidal gels. Colloidal sols
Colloidal state and disperse state
Exact sciences and technology
General and physical chemistry
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A two-step acid/base-catalyzed silica gel has been aged in alcohol and water baths followed by various aprotic solvents with a wide range of surface tensions. Low temperature (CO 2) and high temperature (ethanol) aerogels were also prepared. The physical and chemical structures of gels dried from aprotic solvents were studied by a series of techniques ( 29Si MAS-NMR, nitrogen adsorption, SAXS, elemental analysis, TGA). The aprotic solvents isolated the effects of pore fluid surface tension during drying since they do not participate in condensation and other reactions. For aprotic solvents, a linear decrease in xerogel surface area was observed with increasing surface tension. Pore volume and pore size distribution followed a similar trend. Depending upon whether the gel had been washed in ethanol or water prior to the aprotic solvent, the final pore volume was changed significantly for a given surface tension. This indicates that both surface area and pore volume may be independently controlled.
ISSN:0022-3093
1873-4812
DOI:10.1016/S0022-3093(05)80380-1