Europhys. Lett.
Volume 69, Number 4, February 2005
Page(s) 650 - 656
Section Interdisciplinary physics and related areas of science and technology
Published online 19 January 2005
Europhys. Lett., 69 (4), pp. 650-656 (2005)
DOI: 10.1209/epl/i2004-10382-3

Shape fluctuations and elastic properties of two-component bilayer membranes

A. Imparato, J. C. Shillcock and R. Lipowsky

Max-Planck-Institut für Kolloid- und Grenzflächenforschung 14424 Potsdam, Germany

received 28 July 2004; accepted in final form 7 December 2004
published online 19 January 2005

The elastic properties of two-component bilayer membranes are studied using a coarse-grain model for amphiphilic molecules. The two species of amphiphiles considered here differ only in their length. Molecular-dynamics simulations are performed in order to analyze the shape fluctuations of the two-component bilayer membranes and to determine their bending rigidity. Both the bending rigidity and its inverse are found to be nonmonotonic functions of the mole fraction $x_{\ab{B}}$ of the shorter B-amphiphiles and, thus, do not satisfy a simple lever rule. The intrinsic area of the bilayer also exhibits a nonmonotonic dependence on $x_{\ab{B}}$ and a maximum close to $x_{\ab{B}}
\simeq 1/2$ .

87.16.Dg - Membranes, bilayers, and vesicles.
82.70.-y - Disperse systems; complex fluids.
61.20.Ja - Computer simulation of liquid structure.

© EDP Sciences 2005