X-Ray Scattering Studies of Organic Monolayers on Electrolytic Solutions: Arachidic Acid on CdCl2
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.
KeywordsArachidic Acid Electron Density Profile Full Curve Vertical Density Profile Organic Monolayer
Unable to display preview. Download preview PDF.
- G. L. Gaines, “Insoluble Monolayers at Liquid-Gas Interfaces”; Interscience: New York (1966).Google Scholar
- In ref. , 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 .Google Scholar
- Gmelins Handbuch der Anorganischen Chemie, 33:Cadmium, p. 436. Eighth edition (1959).Google Scholar
- 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
- F. Leveiller, D. Jacquemain, M. Lahav, L. Leiserowitz, M. Deutsch, K. Kjaer and J. Als-Nielsen, Science 252, pp. 1532–1536 (1991).Google Scholar
- 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. , p.443). At higher pH we observed the precipitation of a fine white powder.Google Scholar
- F. Leveiller et al., to be published (1991).Google Scholar
- Five parameters were adjusted to fit ten observed intensities.Google Scholar