Phase Separation in Fluids in the Absence of Gravity Effects

  • D. Beysens
  • P. Guenoun
  • F. Perrot

Abstract

Gravity effects during the phase separation of binary fluids in the critical region have been suppressed by two means: annuling the gravity in a space experiment and/or using a strictly density-matched mixture on earth. Such an isodensity system can be produced by partially deuterating one component in a binary mixture of cyclohexane and methanol. It has been demonstrated that this does not affect the phase transition. Periodic-like patterns can thus be observed. They grow from a microscopic scale up to the final equilibrium stage, determined by the competition between wetting forces, finite volume effects and the remaining gravity influence. These structures are measured as a 2-D section of the 3-D pattern of interfaces between the phase domains. However only interfaces orientated perpendicular to the plane of observation can be detected. This combines with the interconnectivity of the domains to make the visible interface periodicity (Lm) the same as that of domains. After a numerical analysis, the structure factor Ŝ of these interfaces can be obtained, and its scaling properties can be checked. Light-scattering experiments are also reported, so that the scaling properties of the corresponding 3-D structure factor S can be compared to those of Ŝ; especially the equivalence between Lm, as measured from the direct observation or from light-scattering, can be tested, and the difference and similarities between S and Ŝ can be analyzed. Finally emphasis is placed on the possibility of studying quantitatively the phase separation of fluids through this direct observation, and so, even at a microscopic level.

Keywords

Quartz Convection Sedimentation Turbidity Compressibility 

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References

  1. /l/ See e.g. “Phase Transitions” Cargese 1980 ed. by M. Levy, J.C. Le Guillou and J. Zinn-Justin (Plenum, N-Y, 1982).Google Scholar
  2. 2.
    // H. Chaar, M.R. Moldover and J.W. Schmidt, J. Chem. Phys. 85, 418 (1986)CrossRefGoogle Scholar
  3. /3/ See e.g. “Phase Transition and Critical Phenomena” ed. by C. Domb, J.M. Lebowitz (Academic, 1983) Vol.8.Google Scholar
  4. 4.
    // J.W. Cahn, J. Chem. Phys. 42, 93 (1965).CrossRefGoogle Scholar
  5. 5.
    J.S. Langer, M. Bar-On and H.D. Miller, Phys. Rev. All, 1417 (1975)Google Scholar
  6. /5-b/.
    K. Kawasaki and T. Ohta, Progr. Theor. Phys. 59, 362 and 1406 (1978)CrossRefGoogle Scholar
  7. 6.
    K. Binder and D. Stauffer, Phys. Rev. Lett. 33,1006 (1974).CrossRefGoogle Scholar
  8. 7.
    E.D. Siggia, Phys. Rev. A20, 595 (1979).CrossRefGoogle Scholar
  9. 8.
    // K. Binder, C. Billotet and P. Mirold, Z. Phys. B30, 183 (1978).Google Scholar
  10. 9.
    // K. Kawasaki and T. Ohta, Physica 118A. 175 (1983).CrossRefGoogle Scholar
  11. 10.
    // H. Furukawa, Adv. Phys. 34, 703 (1985) and references therein.CrossRefGoogle Scholar
  12. 11.
    M. San Miguel, M. Grant and J.D. Gunton, Phys. Rev. A31, 1001 (1985).CrossRefGoogle Scholar
  13. 12.
    D. Beysens, P. Guenoun and F. Perrot, Submitted to Phys. Rev.A (1987).Google Scholar
  14. 13.
    M. Robert, Phys. Rev. Lett. 54, 44 (1985).CrossRefGoogle Scholar
  15. 14.
    D. Beysens, Acta Astron. 12, 525 (1985).CrossRefGoogle Scholar
  16. 15.
    C. Houessou, P. Guenoun, R. Gastaud, F. Perrot and D. Beysens, Phys. Rev. A32, 1818 (1985).Google Scholar
  17. 16.
    J.W. Cahn, J. Chem. Phys. 66, 3667 (1977).CrossRefGoogle Scholar
  18. 17.
    N.C. Wong and C.M. Knobler, Phys. Rev. A23, 858 (1981).CrossRefGoogle Scholar
  19. 18.
    J.S. Huang, W.I. Goldburg and A.W. Bjerkaas, Phys. Rev. Lett. 32, 921 (1974).CrossRefGoogle Scholar
  20. 18a.
    Y.C. Chou and W.I. Goldburg, Phys. Rev. A20, 2105 (1978);Google Scholar
  21. 19.
    N.C. Wong and C.M. Knobler, J. Chem. Phys. 69, 725 (1978); J. Phys. Chem. 85, 1972 (1981).CrossRefGoogle Scholar
  22. 20.
    R. Hosemann, and J.N. Bagchi, Direct Analysis of Diffraction by Matter (North Holland, Amsterdam 1962).Google Scholar
  23. 21.
    P. Guenoun, R. Gastaud, F. Perrot and D. Beysens, Phys. Rev. A (1987, to appear).Google Scholar
  24. 22.
    J.W. Cahn, J. Chem. Phys. 66, 3667 (1976) For a recent review on Fundamental Problems in Statistical Mechanics VI (E.G.D. Cohen ed., Elsevier, 1985).CrossRefGoogle Scholar
  25. 23.
    P. Guenoun, Thesis (1987, Paris, unpublished).Google Scholar

Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • D. Beysens
    • 1
  • P. Guenoun
    • 1
  • F. Perrot
    • 1
  1. 1.Service de Physique du Solide et de Résonance Magnétique CEN-SaclayGif-sur-Yvette CedexFrance

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