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Anisotropic line tension of domains in lipid monolayers
被引:3
|作者:
Velasco, E.
[1
,2
]
Mederos, L.
[3
]
机构:
[1] Univ Autonoma Madrid, Inst Fis Mat Condensada IFIMAC, Dept Fis Teor Mat Condensada, E-28049 Madrid, Spain
[2] Univ Autonoma Madrid, Inst Ciencia Mat Nicolcis Cabrera, E-28049 Madrid, Spain
[3] CSIC, Inst Ciencia Mat Madrid, C Sor Juana Ines de la Cruz 3, E-28049 Madrid, Spain
关键词:
CRYSTAL PHASE-DIAGRAM;
LANGMUIR MONOLAYER;
TRANSITIONS;
SIMULATIONS;
MODEL;
AIR/WATER;
ORDER;
SHAPE;
D O I:
10.1103/PhysRevE.100.032413
中图分类号:
O35 [流体力学];
O53 [等离子体物理学];
学科分类号:
070204 ;
080103 ;
080704 ;
摘要:
We formulate a simple effective model to describe molecular interactions in a lipid monolayer and calculate the line tension between coexisting domains. The model represents lipid molecules in terms of two-dimensional anisotropic particles on the plane of the monolayer. These particles interact through forces that are believed to be relevant for the understanding of fundamental properties of the monolayer: van der Waals interactions originating from lipid chains and dipolar forces between dipole groups in the molecular heads. The model stresses the liquid-crystalline nature of the ordered phase in lipid monolayers and explains coexistence properties between ordered and disordered phases in terms of molecular parameters. Thermodynamic and interfacial properties of the model are analyzed using density-functional theory. In particular, the line tension at the interface between ordered and disordered phases turns out to be highly anisotropic with respect to the angle between the nematic director and the interface separating the coexisting phases. This important feature mainly results from the tilt angle of lipid chains and, to a lesser extent, from dipolar interactions perpendicular to the monolayer. The role of the two dipolar components, parallel and perpendicular to the monolayer, is assessed by comparing with computer simulation results for lipid monolayers.
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页数:11
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