Contact angle measurement and its application to sol-gel processing
- Univ. of New Mexico, Albuquerque, NM (United States). UNM/NSF Center for Micro-Engineered Ceramics
Capillary stresses during drying that result from the contact angle of a liquid solvent to a gel, surface tension, and pore size have an immense effect on the dried gel. The extent to which the gel shrinks is a balance between the capillary stress and the solid matrix strength. The dynamic contact angles and surface tensions of various solvents commonly employed in sol-gel processing on silica gels of various surface chemistries have been evaluated. A thin, dense coating of silica gel was formed by dip coating a standard glass slide in an acid catalyzed silica sol and drying. Some of the sample surfaces were organically modified. Dynamic contact angles were determined using a modified Wilhelmy plate technique. Solvent surface tensions were determined using the De Nouy ring technique. The bulk modulus of wet gels were determined with a three point bend experiment. The authors have found that contrary to previous investigators, who attributed different bulk densities obtained after drying from various alcohols to contact angles variations, gel shrinkage during drying is actually due to slightly different surface tensions and degrees of depolymerization of the gel network.
- OSTI ID:
- 51625
- Report Number(s):
- CONF-940411-; ISBN 1-55899-246-4; TRN: IM9524%%90
- Resource Relation:
- Conference: Spring meeting of the Materials Research Society (MRS), San Francisco, CA (United States), 4-8 Apr 1994; Other Information: PBD: 1994; Related Information: Is Part Of Better ceramics through chemistry VI. Materials Research Society symposium proceedings Volume 346; Cheetham, A.K. [ed.] [Univ. of California, Santa Barbara, CA (United States)]; Brinker, C.J. [ed.] [Sandia National Labs., Albuquerque, NM (United States)]; Mecartney, M.L. [ed.] [Univ of California, Irvine, CA (United States)]; Sanchez, C. [ed.] [Univ. Pierre et Marie Curie, Paris (France)]; PB: 1069 p.
- Country of Publication:
- United States
- Language:
- English
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