DIELECTRIC STUDY OF THE DILUTE PART OF A SDS BRINE/ALCOHOL SYSTEM - ANEW SEQUENCE OF PHASES/

We discuss in this letter the dilute part of the phase diagram of the pseudo-ternary system (brine + glycerol), SDS, hexanol through Freeze Fracture Electron Microscopy (FFEM) and dielectric measurements. The m ain conclusion is the observation of a large one-phase domain L inste ad of an L4 phase as usually found in similar systems. This L domain is connected to the sponge domain, through paths surrounding the lamel lar phase. We show by FFEM that samples in the L domain are mostly co mposed of vesicles. However, they present a dielectric behavior differ ent from a vesicle phase. We conclude that L is not a vesicle phase b ut is a sponge phase whose topology is different from the one found in the concentrated part of the L3 phase (see GAZEAU D., BELLOCQ A. M., Roux D. and ZEMB T., Europhys. Lett., 9 (1989) 447 and FORTE G., MARIG NAN J., BASSEREAU P. and MAY R. J. Phys. (Paris), 49 (1988) 511). Thes e results bring new light on the sponge stability.