DOI: 10.1140/epje/i2002-10125-x
Lateral and transverse diffusion in two-component bilayer membranes
A. Imparato, J.C. Shillcock and R. LipowskyMax-Planck-Institut für Kolloid- und Grenzflächenforschung, Abteilung Theorie, D-14424 Potsdam, Germany imparato@mpikg-golm.mpg.de
shillcock@mpikg-golm.mpg.de
lipowsky@mpikg-golm.mpg.de
(Received 6 December 2002 and Received in final form 26 March 2003 / Published online: 27 May 2003)
Abstract
We study the lateral and transverse
diffusion of amphiphiles in
two-component bilayer membranes, using a coarse-grained model for amphiphilic
molecules and combined Monte Carlo-Molecular Dynamics simulations.
Membrane structural properties, such as the mean thickness, are also measured.
The dependence of such properties on membrane composition,
inter-molecular
interactions, and amphiphile stiffness is determined.
In particular, we show that addition of
shorter amphiphiles drives the model membrane towards a more fluid state,
with increased amphiphile lateral diffusion rates. These results can be
understood in the framework of a simple free-volume model.
Furthermore, we observe an increase in the trans-membrane diffusion
when the interaction energy of amphiphiles with their neighboring
molecules is decreased.
82.70.-y - Disperse systems; complex fluids.
61.20.Ja - Computer simulation of liquid structure.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003
