Europhys. Lett.
Volume 72, Number 5, December 2005
Page(s) 767 - 773
Section Condensed matter: structural, mechanical and thermal properties
Published online 03 November 2005
Europhys. Lett., 72 (5), pp. 767-773 (2005)
DOI: 10.1209/epl/i2005-10307-8

Solid domains in lipid vesicles and scars

Y. Chushak and A. Travesset

Physics Department, Iowa State University - Ames, IA, 50011, USA and Ames Lab - Ames, IA, 50011, USA

received 23 June 2005; accepted in final form 4 October 2005
published online 3 November 2005

The free energy of a crystalline domain coexisting with a liquid phase on a spherical vesicle may be approximated by an elastic or stretching energy and a line tension term. The stretching energy generally grows as the area of the domain, while the line tension term grows with its perimeter. We show that if the crystalline domain contains defect arrays consisting of finite-length grain boundaries of dislocations (scars), the stretching energy grows linearly with a characteristic length of the crystalline domain. We show that this result is critical to understand the existence of solid domains in lipid-bilayers in the strongly segregated two-phase region even for small relative area coverages. The domains evolve from caps to stripes that become thinner as the line tension is decreased. We also discuss the implications of the results for other experimental systems and for the general problem that consists in finding the ground state of a very large number of particles constrained to move on a fixed geometry and interacting with an isotropic potential.

62.20.Dc - Elasticity, elastic constants.
61.72.Lk - Linear defects: dislocations, disclinations.
87.16.Dg - Membranes, bilayers, and vesicles.

© EDP Sciences 2005