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Drying Mechanics of Gels

Published online by Cambridge University Press:  28 February 2011

George W. Scherer*
Affiliation:
E. I. du Pont de Nemours & Co., Central R & D Dept., Experimental Station 356/384, Wilmington, DE 19898 USA
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Abstract

A model is presented for the stresses and strains that develop in a gel during drying. The driving force for shrinkage is assumed to be the interfacial energy, and the gel is considered to be viscoelastic. The liquid seeks to flow into the dry region of a gel in order to replace the solid-vapor interface with a solid-liquid interface having lower specific energy. This creates a “redistribution pressure” that causes the wet region to contract. The free contraction rate can be calculated by equating the decrease in surface energy with the energy dissipated in viscous flow as the gel contracts. The permeability of the gel to the liquid in the pores is especially important in the early stages of drying, and may control the contraction rate. The model allows quantitative predictions of contraction rate and stress during drying. In this paper, the model is applied to a plate drying from both sides.

Type
Articles
Copyright
Copyright © Materials Research Society 1986

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References

REFERENCES

1. Zarzycki, J., Prassas, M., and Phalippou, J., J. Mater. Sci., 17, 3371 (1982)Google Scholar
2. Tewari, P.H., Hunt, A.J., and Loftus, R.D., Mater. Lett., 3 (9–10) 363 (1985)Google Scholar
3. Wallace, S. and Hench, L.L.in Better Ceramics Through Chemistry, eds. Brinker, C.J., Clark, D.E., and Ulrich, D. R., p.47, North-Holland, NY, 1984 Google Scholar
4. Cooper, A. R. in Ceramics Processing Before Firing, eds. Onoda, G.Y. Jr. and Hench, L.L., p. 261, John Wiley & Sons, NY, 1978 Google Scholar
5. Macey, H.H., Trans. Brit. Cer. Soc., 41 (4) 73121 (1942)Google Scholar
6. Smiles, D.E., Soil Science, 117 (3) 140147 (1974)Google Scholar
7. Tanaka, T. and Fillmore, D.J., J. Chem. Phys., 70 (3) 12141218 (1979)Google Scholar
8. Scherer, G.W., “Drying Gels: I. General Theory”, submitted for publication in J. Non-Crystalline SolidsGoogle Scholar
9. Scherer, G.W., J. Am. Ceram. Soc.,. 60 (5–6) 236 (1977)Google Scholar
10. Scherer, G.W., “Viscous Sintering of Inorganic Gels”, to be published in Surface and Colloid Science, Vol.14, ed. Matijevic, E., John Wiley & Sons, NY Google Scholar
11. Scherer, G.W., Brinker, C.J., and Roth, E.P., J. Non-Crystalline Solids, 72, 369389 (1985)Google Scholar
12. Scherer, G.W., “Drying Gels: II. Film and Flat Plate”, submitted for publication in J. Non-Crystalline SolidsGoogle Scholar