Monte Carlo simulations of a polymer confined within a fluid vesicle

Monte Carlo simulations are employed to study a fluid vesicle that contains a single worm-like polymer chain. The contour length of the polymer is about five times the circumference of the nominally spherical vesicle. We vary the degree of polymer confinement in our simulations by increasing the per...

Full description

Saved in:
Bibliographic Details
Published in:Soft matter 2013-01, Vol.9 (15), p.3976-3984
Main Authors: Fošnari, Miha, Igli, Aleš, Kroll, Daniel M, May, Sylvio
Format: Article
Language:English
Subjects:
Asphericity
Coiling
Computer simulation
Fluid dynamics
Fluid flow
Mathematical analysis
Monte Carlo methods
Vesicles
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Monte Carlo simulations are employed to study a fluid vesicle that contains a single worm-like polymer chain. The contour length of the polymer is about five times the circumference of the nominally spherical vesicle. We vary the degree of polymer confinement in our simulations by increasing the persistence length of the polymer. The vesicle is represented by a randomly triangulated self-avoiding network that can undergo bending deformations. Upon increasing the persistence length of the polymer beyond the size of the vesicle, we observe a transition of the polymer from an isotropic disordered random conformation to an ordered toroidal coil. Concomitantly, the vesicle adopts an oblate shape to allow for some expansion of the polymer coil inside the vesicle. It is convenient to characterize both polymer and vesicle in terms of the asphericity, a quantity derived from the gyration tensor. At the onset of the polymer's ordering transition, the asphericity passes through a minimum for both polymer and vesicle. The increase in vesicle asphericity for a semi-flexible polymer can be understood in terms of ground state energy calculations, either for a simplified representation of the vesicle shape (we specifically discuss a disk shape with a semi-toroidal rim) or involving a full vesicle shape optimization. The asphericity of the polymer coil results from conformational fluctuations and can be rationalized using Odijk's deflection length of strongly curved semi-flexible polymers. The conformations of a fluid-like lipid vesicle that encloses a single worm-like polymer are studied using Monte Carlo simulations and phenomenological modeling.
ISSN:1744-683X
1744-6848
DOI:10.1039/c3sm27938c