Transitions between mesophases involving cubic phases in the surfactant-water systems. Epitaxial relations and their consequences in a geometrical framework

Abstract

In order to approach the fascinating structure of the cubic mesophases, we study phase transitions involving them and another mesophases with simpler structures. In the first part, we give some results obtained in the C12EO6/water binary system, that exhibits the most frequent case of bicontinuous cubic mesophase, with space group Ia3d, and two transitions toward the hexagonal and lamellar mesophases. X-ray scattering experiments and some optical observations in polarized light are presented for oriented single-domains of the mesophases. In the second part, we propose some topological arguments to explain the transformations involved at these two transitions and propose some possible fluctuations associated with them