A disordered lamellar structure in the isotropic phase of a ternary double-chain surfactant system

Ian S. Barnes , Paul-Joël Derian , Stephen T. Hyde , Barry W. Ninham , Thomas Zemb

The « anomalous » fluid isotropic phase in the DDAB/tetradecane/water system differs in important ways from microemulsion phases in related systems, and is thus a useful test for models. On the basis of absolute scaled neutron and X-ray scattering data we show here that the microstructure is best characterised as a randomly folded reverse bilayer. All previously reported examples of this structure are restricted to a narrow range of composition and temperature. In this case of a stiff bilayer with low spontaneous interfacial curvature it extends over a large region of the ternary phase diagram at room temperature, the boundaries of which are explained in terms of simple geometric constraints. Other possible microstructures are critically reviewed.

Mots clés: emulsions; liquid structure; neutron diffraction examination of liquids; phase diagrams; X ray diffraction examination of liquids

Domaines: Articles anciens

Ian S. Barnes, Paul-Joël Derian, Stephen T. Hyde, Barry W. Ninham, Thomas Zemb. A disordered lamellar structure in the isotropic phase of a ternary double-chain surfactant system. Journal de Physique, 1990, 51 (22), pp.2605-2628. ⟨10.1051/jphys:0199000510220260500⟩. ⟨jpa-00212557⟩