Small-angle X-ray scattering from ternary microemulsions determines microstructure

Abstract

The microstructure of the L2 phase formed from ternary mixtures of water, didodecyldimethylammonium bromide, and various alkanes or mixtures thereof has been interpreted by small-angle X-ray scattering (SAXS). The scattering spectra indicate a wide variation in microstructure within a single phase and are explained quantitatively. So, too, are the percolation transitions in conductance and the demixing boundary in the ternary phase diagram. Only a single parameter, the measured curvature at the oil-water interface, is required for each alkane. The topology of the microstructure varies with oil and water composition, with structures ranging from highly interconnected bicontinuous networks of water and oil to monodisperse spheres. Show more