Equilibrium onions?L. Ramos1, D. Roux2, P. D. Olmsted3 and M. E. Cates4
1 Groupe de Dynamique des Phases Condensées (UMR CNRS-UM2 5581), CC26 Université Montpellier 2 - 34095 Montpellier Cedex 5, France
2 Centre de Recherche Paul Pascal - avenue Schweitzer, 33600 Pessac, France
3 Department of Physics and Astronomy & Polymer IRC, University of Leeds Leeds LS2 9JT, UK
4 School of Physics, University of Edinburgh, JCMB Kings Buildings Mayfield Road, Edinburgh EH9 3JZ, UK
(Received 30 July 2003; accepted in final form 15 April 2004)
We demonstrate the possibility of a stable equilibrium multi-lamellar ("onion") phase in pure lamellar systems (no excess solvent) due to a sufficiently negative Gaussian curvature modulus. The onion phase is stabilized by non-linear elastic moduli coupled to a polydisperse size distribution (Apollonian packing) to allow space-filling without appreciable elastic distortion. This model is compared to experiments on copolymer-decorated lamellar surfactant systems, with reasonable qualitative agreement.
82.70.Uv - Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems (hydrophilic and hydrophobic interactions).
68.18.Jk - Surface and interfaces; thin films and low-dimensional systems (structures and nonelectric properties): Phase transitions.
61.30.St - Lyotropic phases.
© EDP Sciences 2004