Issue
Europhys. Lett.
Volume 73, Number 6, March 2006
Page(s) 871 - 877
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
DOI http://dx.doi.org/10.1209/epl/i2005-10476-4
Published online 08 February 2006
Europhys. Lett., 73 (6), pp. 871-877 (2006)
DOI: 10.1209/epl/i2005-10476-4

Surface relaxation of lyotropic lamellar phases

H. Bary-Soroker1 and H. Diamant2

1  School of Physics & Astronomy, Raymond & Beverly Sackler Faculty of Exact Sciences Tel Aviv University - Tel Aviv 69978, Israel
2  School of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences Tel Aviv University - Tel Aviv 69978, Israel

hdiamant@tau.ac.il

received 19 July 2005; accepted in final form 23 January 2006
published online 8 February 2006

Abstract
We study the relaxation modes of an interface between a lyotropic lamellar phase and a gas or a simple liquid. The response is found to be qualitatively different from those of both simple liquids and single-component smectic-A liquid crystals. At low rates it is governed by a non-inertial, diffusive mode whose decay rate increases quadratically with wave number, $\vert\omega\vert=Aq^2$. The coefficient A depends on the restoring forces of surface tension, compressibility and bending, while the dissipation is dominated by the so-called slip mechanism, i.e., relative motion of the two components of the phase parallel to the lamellae. This surface mode has a large penetration depth which, for sterically stabilised phases, is of order (dq2)-1, where d is the microscopic lamellar spacing.

PACS
61.30.St - Lyotropic phases.
68.03.Kn - Gas-liquid and vacuum-liquid interfaces: Dynamics (capillary waves).
82.70.Uv - Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems (hydrophilic and hydrophobic interactions).

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