Abstract. 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.

PACS numbers: 82.70.Uv, 68.18.Jk, 61.30.St

Print publication: Issue 6 (June 2004)
Received 30 July 2003, in final form and accepted for publication 15 April 2004