Abstract
It was previously shown [J. Non-Cryst. Solids, 130, 157 (1991)] that the permeability of a saturated gel can be determined from a measurement of its rate of expansion during a change in temperature. The existing analysis assumes that the solid network of the gel behaves elastically, but in many cases the gel is likely to be viscoelastic, especially when the gel exhibits syneresis. In this paper, the expansion kinetics are determined for a gel with a viscoelastic (VE) network. Sample calculations for a silica gel containing ethanol indicate that a naive application of the elastic analysis could result in errors exceeding a factor of two in the estimate of the permeability of a VE gel. However, in such cases, there are qualitative features in the experimental data that alert the experimenter to the existence of significant VE relaxation. Therefore, it is possible to avoid errors by careful examination of the data.
Similar content being viewed by others
References
G.W. Scherer, H. Hdach, and J. Phalippou, J. Non-Cryst. Solids, 130, 157–170 (1991); correction, 136, 269 (1991).
C.J. Brinker and G.W. Scherer, Sol-Gel Science (Academic Press, NY, 1990), Ch. 6.
G.W. Scherer, in Better Ceramics Through Chemistry V, eds. (Materials Research Society, Pittsburgh, PA, 1992), pp. 527–533.
G.W. Scherer, J. Non-Cryst. Solids, 142 (1–2), 18–35 (1992).
G.W. Scherer, J. Sol-Gel Sci. Tech., 1, 169–175 (1994); J. Sol-Gel Sci. Tech., 2, 199–204 (1994).
M.A. Biot, J. Appl. Phys., 33 (4), 1482–1498 (1962).
G.W. Scherer, Relaxation in Glasses and Composites (Wiley, New York, 1986), Ch. 7.
C.J. Brinker and G.W. Scherer, Sol-Gel Science (Academic Press, NY, 1990), Ch. 7.
F.B. Hildebrand, Advanced Calculus for Applications (Prentice-Hall, Englewood Cliffs, NJ, 1962), Ch. 2.
G.W. Scherer, J. Am. Ceram. Soc., 69 (5), 374–381 (1986) (see Appendix B).
J.D. Rimstedt and H.L. Barnes, Geochim. Cosmochim. Acta, 44, 1683 (1980).
IMSL Math/Library, Version 1.1, IMSL Inc., 2500 City West Blvd., Houston, TX 77042-3020, USA.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Scherer, G.W. Thermal expansion of a viscoelastic gel. J Sol-Gel Sci Technol 4, 169–177 (1995). https://doi.org/10.1007/BF00488371
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00488371