Europhys. Lett.
Volume 69, Number 5, March 2005
Page(s) 839 - 845
Section Interdisciplinary physics and related areas of science and technology
Published online 04 February 2005
Europhys. Lett., 69 (5), pp. 839-845 (2005)
DOI: 10.1209/epl/i2004-10423-y

Monte Carlo calculations of the free-energy landscape of vesicle formation and growth

S.-J. Zhao and J. T. Kindt

Department of Chemistry, Emory University - Atlanta, GA, 30322, USA

received 25 August 2004; accepted in final form 7 January 2005
published online 4 February 2005

A flat-histogram Monte Carlo sampling method is used to calculate the free-energy landscape of a simple semi-flexible triangulated membrane model as a function of the number of vertices and the number of free edges. Results yield the equilibrium ratio of open (disk) and closed (vesicle) states, the free-energy barrier between these states, and the scaling of vesicle free energy with size N in the range from 6 to 200 vertices. Deviations from the predictions of a simple model for the disk-vesicle transition are found to result from the fluctuations of the edge. Vesicle free energies are fit to the form $BN+\nu k_{\ab{B}}T\ln N$, with coefficient $\nu=1.6\pm0.1$ for flexible membranes (consistent with self-avoiding branched polymer statistics) and $1.2\pm0.1$ for semiflexible membranes.

87.16.Dg - Membranes, bilayers, and vesicles.
87.15.Aa - Theory and modeling; computer simulation.

© EDP Sciences 2005