Issue
J. Phys. France
Volume 51, Number 14, juillet 1990
Page(s) 1501 - 1508
DOI https://doi.org/10.1051/jphys:0199000510140150100
J. Phys. France 51, 1501-1508 (1990)
DOI: 10.1051/jphys:0199000510140150100

Symmetry transition in the cubic phase of a ternary surfactant system

S. Radiman1, C. Toprakcioglu1, 2 et A.R. Faruqi3

1  Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 OHE, G.B.
2  AFRC Institute of Food Research, Colney Lane, Norwich NR4 7UA, G.B.
3  MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, G.B.


Abstract
We report a small-angle X-ray and neutron scattering investigation in the cubic phase of the ternary system water/didodecyldimethyl ammonium bromide (DDAB)/octane. We have observed a systematic variation in the lattice parameter as a function of water content, which can be related to the change in interfacial area per unit cell with the aqueous volume fraction. Our results are consistent with a bicontinuous periodic constant mean curvature structure, and show a transition from diamond to body-centred cubic symmetry on increasing the water content of the system.

PACS
8270K - Emulsions and suspensions.
6130 - Liquid crystals.

Key words
emulsions -- lipid bilayers -- liquid crystals -- neutron diffraction examination of materials -- organic compounds -- phase diagrams -- water -- X ray diffraction examination of materials