Springer LINK: The European Physical Journal B - Abstract Volume 4 Issue 3 (1998) pp 333-340

The European Physical Journal B

ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)

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Abstract Volume 4 Issue 3 (1998) pp 333-340

Micelle-smectic phase coexistence: Origin of the maximum swelling of a mixed lamellar phase

F. Ricoul (1) (a), M. Dubois (1), T. Zemb (1), D. Plusquellec (2)

(1) Service de Chimie Moléculaire, bâtiment 125, CEA/Saclay, 91191 Gif-sur-Yvette, France
(2) E.N.S.C.R., avenue du Général Leclerc, 35700 Rennes, France

Received: 30 December 1997 / Accepted: 14 April 1998

Abstract: We use the water corner of the model ternary system water/DDAB (a cationic double tailed surfactant)/LS (an uncharged single chain glycolipid) to investigate maximum swelling of a charged lamellar phase. The phase diagram is determined by visual observation and small angle neutron scattering. Upon the addition of the glycolipid in this mixed lamellar structure, a decrease of the maximum swelling is observed. A transition from vesicles to micelles is also evidenced in the dilute coexisting phase. By calculating explicitly the osmotic pressure in the micellar phase and in the lamellar phase through the Poisson-Boltzmann equation, we demonstrate that equilibrium of the osmotic pressure in the two phases and depletion of the lamellar phase by the micellar phase explain quantitatively the decrease of maximum swelling observed when the LS to DDAB ratio increases.

PACS. 61.12.Ex Neutron scattering techniques (including small-angle scattering) - 64.70.Md Transitions in liquid crystals - 82.70.Dd Colloids

(a) Present address: SPHA/LEPI, CEA/Valrhô, bâtiment 57, Marcoule, BP 171, 30207 Bagnols-sur-Cèze Cedex, France. email: ricoul@genoise.cea.fr

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