A NEW SYMMETRY FOR THE PACKING OF AMPHIPHILIC DIRECT MICELLES

Thanks to X-ray scattering, we have studied the C(12)EO(8)/water binar y system in the region located between the isotropic phase and the dir ect hexagonal mesophase. We have discovered two SD-periodic phases in this region: one with a cubic symmetry (space group Pm(3) over bar n), the other with a hexagonal symmetry (space group p6(3)/mmc). Both pha ses consist in a regular packing of direct micelles build with the sur factant molecules in water. The cubic phase have already been observed in other lyotropic systems. On the other hand, the hexagonal phase is a new type of structure for such systems. We assume for this phase a hexagonal compact structure.