Electron Microscopy Study of Hα → Qα Transition Phase in a Sodium Dodecylsulfate-Formamide (SDS-Formamide) System

Abstract

The study of the SDS-Formamide system by freeze-fracture electron microscopy revealed in addition to hexagonal phase Hα and the cubic phase Qα the existence of a structure with flexible cylinders. This structure is located in the diagram of phases between hexagonal phase Hα (p6m) and cubic phase Qα (Ia3d) and is characterised by defects (dislocations, disinclinaisons, focal domains, flexion and torsion boundaries). The hexagonal phase thus appears under two morphological varieties: a variety with rigid cylinders on the side low in surfactant and a variety with flexible cylinders on the side rich in surfactant. Any fractures present a network with square meshes revealing thus the cubic Qα(Ia3d). We think that the structure with flexible cylinders observed by electron microscopy is a stage to wards the transition Hα-Qα whose we will have the results.