Eur. Phys. J. B 10, 53-60 (1999)
https://doi.org/10.1007/s100510050829

Curvature walls and focal conic domains in a lyotropic lamellar phase

Laboratoire de Minéralogie-Cristallographie de Paris (UMR 7590) , T16 case 115, 4 place Jussieu, 75252 Paris Cedex 05, France

Corresponding author: ^a blanc@lmcp.jussieu.fr

Received: 4 November 1998
Published online: 15 July 1999

Abstract

In the quasi-ternary CPCl/brine/hexanol lyotropic system, the interface of the L_α lamellar and L₃ sponge phases displays a phenomenon of epitaxy: the layers of the lamellar phase tend to make a constant non-trivial angle with the interface. Thin samples of lamellar phase embedded in the sponge phase are thus submitted to oblique anchoring conditions and defects are created in the lamellar phase in order to satisfy the bulk lamellar ordering and the boundary conditions. We have studied small droplets of lamellar phase in the sponge phase. They do not exhibit the classic L_α defects (focal conic domains) but wall defects, which appear in order to satisfy the smectic elasticity and the boundary conditions. Moreover we show through experiments in controlled geometry that, even in the presence of focal conic domains, wall defects control the size and periodicity of the textures which are observed at the interface.