Dynamic Behaviour of Ternary Microemulsions Consisting of Didodecyldimethylammoniumbromide, Water and Hydrocarbon

Abstract

Ternary micromulsions containing water, dodecane and the surfactant didodecyldimethylammoniumbromide (DDABr) have been studied with flow and electric birefringence methods as well as with pressure jump relaxation techniques and conductivity measurements. Previous measurements had shown, that the isotropic L2-phase can be subdivided into an area with spherical droplets and an area with interconnected water channels. Unexpectedly, a large birefringence was found within the region of the spheres and only small amplitudes in the other subregion. Kinetically measured relaxation times agree well with the rotation times which were determined from the birefringence methods. It is supposed that the water droplets are of ellipsoidal shape. The rotational diffusion time constants were determined from the birefringence signals. Both techniques gave the same results. The rotation time constants and the amplitudes of the birefringence signals increase with increasing water content. For large W/S ratios no large changes in the birefringence signals were observed in the percolation region of the conductivity. The measurements furthermore show that the lifetimes of both the globules and the channels are short and in the range of μs.