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Preparation of Low-Density Aerogels at Ambient Pressure

Published online by Cambridge University Press:  25 February 2011

Douglas M. Smith ,
Ravindra Deshpande  and
C. Jeffrey Brinke
Douglas M. Smith
Affiliation:
UNM/NSF Center for Micro-Engineered Ceramics, University of New Mexico, Albuquerque NM 87131.
Ravindra Deshpande
Affiliation:
UNM/NSF Center for Micro-Engineered Ceramics, University of New Mexico, Albuquerque NM 87131.
C. Jeffrey Brinke
Affiliation:
UNM/NSF Center for Micro-Engineered Ceramics, University of New Mexico, Albuquerque NM 87131.
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Abstract

Low density aerogels have numerous unique properties which suggest a number of applications such as ultra high efficiency thermal insulation. However, the commercial viability of these materials has been limited by the high costs associated with drying at high pressures (supercritical), low stability to water vapor, and low mechanical strength. Normally, critical point drying is employed to eliminate the surface tension and hence, the capillary pressure, of the pore fluid to essentially zero. However, we show that by employing a series of aging and surface derivatization steps, the capillary pressure and gel matrix strength may be controlled such that gel shrinkage is minimal during rapid drying at ambient pressure. The properties (density, surface area, pore size, SAXS) of aerogel monoliths prepared from base catalyzed silica gels using this technique, supercritical CO2 drying, and supercritical ethanol drying are compared. An additional advantage of this approach is that the final gels are hydrophobic.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 271: Symposium N – Better Ceramics Through Chemistry V , 1992 , 567
Copyright
Copyright © Materials Research Society 1992

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References

REFERENCES

[1] Hrubesh, L. W., Chemistry and Industry, 24, 824 (1990).Google Scholar
[2] Fricke, J. and Caps, R. in Ultrastructure Processing of Advanced Ceramics edited by Mackenzie, J. D. and Ulrich, D. R. (Wiley, New York, 1988), p. 613.Google Scholar
[3] Fricke, J. in Sol-Gel Technology for Thin Films. Fibers. Preforms. Electronics and Speciality Shapes edited by Klein, L. C. (Noyse Publications, Park Ridge NJ, 1988), p. 226.Google Scholar
[4] Brinker, C. J. and Scherer, G. W., Sol-Gel Science (Academic Press, San Diego, 1990).Google Scholar
[5] Smith, D. M., Glaves, C. L., Davis, P. J., and Brinker, C. J., In Situ NMR Study of Gel Pore Structure During Drying and Aging in Better Ceramics Through Chemistry III edited by Brinker, C. J., Clark, D. E., and Ulrich, D. R. (Mater. Res. Soc. Proc. 121, Pittsburgh, PA 1988) pp.657–662.Google Scholar
[6] Davis, P. J., Brinker, C. J. and Smith, D. M., Journal of Non-Crystalline Solids, in press.Google Scholar
[7] Davis, P. J., Brinker, C. J., Smith, D. M. and Assink, R. A., Journal of Non-Crystalline Solids, in press.Google Scholar
[8] Deshpande, R., Hua, D. W., Brinker, C. J. and Smith, D. M., Journal of Non-Crystalline Solids, in press.Google Scholar
[9] Kistler, S. S., Nature, 127, 741 (1931).Google Scholar
[10] Deshpande, R., Smith, D. M., Brinker, C. J., U. S. Patent Application, 1992.Google Scholar
[11] Brinker, C. J., Keefer, K. D., Schaefer, D. W., and Ashley, C. S., J. Non- Crystalline Solids, 48, 47 (1982).Google Scholar
[12] Scherer, G. W., Hdach, H., and Phalippou, J., Journal of Non-Crystalline Solids, 130 (1991) 157.Google Scholar