X-Ray Scattering Studies of Organic Monolayers on Electrolytic Solutions: Arachidic Acid on CdCl2

  • K. Kjaer
  • J. Als-Nielsen
  • R. M. Kenn
  • C. Böhm
  • P. Tippmann-Krayer
  • C. A. Helm
  • H. Möhwald
  • F. Leveiller
  • D. Jacquemain
  • M. Lahav
  • L. Leiserowitz
  • M. Deutsch
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 61)

Abstract

The interaction between a charged monolayer of fatty acid molecules on the surface of a CdCl2 aqueous solution and the ions below has been investigated by means of X-ray Reflection and Grazing-Incidence Diffraction. A stoichiometric, localised layer of Cd++ ions forms an epitaxial 2×3 superstructure below the 2D-crystalline fatty acid monolayer.

Keywords

Surfactant Petroleum Cadmium CdCl2 Coherence 

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References

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    G. L. Gaines, “Insoluble Monolayers at Liquid-Gas Interfaces”; Interscience: New York (1966).Google Scholar
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    K. Kjaer, J. Als-Nielsen, C. A. Helm, P. Tippmann-Krayer and H. Möhwald, J. Phys. Chem. 93, pp. 3200–6 (1989).CrossRefGoogle Scholar
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    In ref. [2], pH was adjusted with NaOH and could not be determined very accurately. We estimate now that pH was about 7, high enough to completely dissociate COOH to COO-. At higher pH, precipitation occurs [4].Google Scholar
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    Gmelins Handbuch der Anorganischen Chemie, 33:Cadmium, p. 436. Eighth edition (1959).Google Scholar
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    J. Als-Nielsen and K. Kjaer, In: “Phase Transitions in Soft Condensed Matter”; T. Riste and D. Sherrington, Eds; Proc. NATO ASI Series B 211, Plenum: New York, pp. 113–138 (1989).Google Scholar
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    pH was adjusted with NH3 and measured to within 0.1. The use of NH3 allows pH ≤ 8.8 due to the formation of the complexe Cd(NH3)++ 4 (cf. ref. [4], p.443). At higher pH we observed the precipitation of a fine white powder.Google Scholar
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    F. Leveiller et al., to be published (1991).Google Scholar
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    Five parameters were adjusted to fit ten observed intensities.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1992

Authors and Affiliations

  • K. Kjaer
    • 1
  • J. Als-Nielsen
    • 1
  • R. M. Kenn
    • 2
  • C. Böhm
    • 2
  • P. Tippmann-Krayer
    • 2
  • C. A. Helm
    • 2
  • H. Möhwald
    • 2
  • F. Leveiller
    • 3
  • D. Jacquemain
    • 3
  • M. Lahav
    • 3
  • L. Leiserowitz
    • 3
  • M. Deutsch
    • 4
  1. 1.Physics DepartmentRisø National LaboratoryRoskildeDenmark
  2. 2.Physical Chemistry DepartmentMainz UniversityMainzFed. Rep. of Germany
  3. 3.Structural Chemistry DepartmentWeizmann InstituteRehovotIsrael
  4. 4.Physics DepartmentBar-Ilan UniversityRamat-GanIsrael

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