Advertisement

Acoustic spectroscopy of aerogel precursors

Conference paper
Part of the Progress in Colloid and Polymer Science book series (PROGCOLLOID, volume 115)

Abstract

We investigate the acoustical properties of silica gels, which are precursors in the aerogel production process. These gels exhibit a strong “ringing gel” behavior, that is they emit a characteristic sound if one knocks against the container. We study this sound emission with a very simple spectroscopic technique and observe resonances which are characteristic for natural frequencies of a cylindrical body. From a fit of the experimental frequency positions to calculated values, we determine a sound velocity of c T = 4 m/s for a gel sample with porosity φ = 97.5%. This low sound velocity can only be interpreted as the transverse sound mode predicted by Biot’s theory for sound propagation in porous media.

Key words

Acoustic properties Porous materials Silica gels Aerogels 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Oetter G, Hoffmann H (1989) Colloids Surf A 38:225CrossRefGoogle Scholar
  2. 2.
    Gradzielski M, Hoffmann H, Oetter G (1990) Colloid Polym Sci 268:167CrossRefGoogle Scholar
  3. 3.
    Bacri JC, Dumas J, Levelut A (1979) J Phys Lett 40:L231CrossRefGoogle Scholar
  4. 4.
    Biot MA (1962) J Appl Phys 33:1482CrossRefGoogle Scholar
  5. 5.
    Forest L, Gibiat V, Woignier T (1998) J Non-Cryst Solids 225:287CrossRefGoogle Scholar
  6. 6.
    Johnson DL (1982) J Chem Phys 77:1531CrossRefGoogle Scholar
  7. 7.
    Landau LD, Lifshitz EM (1991) Lehrbuch der Theoretischen Physik, Band VI: Hydrodynamik. Academie-Verlag, BerlinGoogle Scholar
  8. 8.
    Wood AW (1941) A Textbook of sound. Macmillan, New YorkGoogle Scholar
  9. 9.
    Tanaka T, Hocker LO, Benedek GB (1973) J Chem Phys 59:5151CrossRefGoogle Scholar
  10. 10.
    Abramowitz M, Stegun IA (1972) Handbook of mathematical functions. Dover, New YorkGoogle Scholar

Copyright information

© Springer-Verlag 2000

Authors and Affiliations

  • C. Sinn
    • 1
    • 2
  1. 1.Institut für Physik derJohannes-Gutenberg-UniversitätMainzGermany
  2. 2.Institut für Angewandte Physik derUniversität BernBernSwitzerland

Personalised recommendations