J. Phys. II France
Volume 7, Numéro 6, June 1997
Page(s) 815 - 824
DOI: 10.1051/jp2:1997153
J. Phys. II France 7 (1997) 815-824

Effect of Symmetry on a Three-Component Lamellar Phase: X-ray Scattering Study

R. Oda and J.D. Litster

Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

(Received 6 May 1996, revised 8 January 1997, accepted 4 March 1997)

X-ray scattering data of a three-component lamellar phase composed of oil (octane), water and a non-ionic surfactant $({\rm C}_{12}{\rm E}_5)$ are shown for various surfactant concentrations as well as oil/water volume ratios, in order to study the periodicity of the layers as well as the effect of structural symmetry on their interactions and organization of the layers. The data are fitted with a recently proposed model which takes into account the geometry and the fluctuations of these repeated structures and gives a good fit for a highly fluctuating non-charged and non-oriented lamellar phase. The variation of the exponent $\eta$ which characterizes the quasi-long range order indicates that the structure is more ordered for the most symmetrical system: i.e. for an oil/water ratio of 1.

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