Bilayers connected by threadlike micelles in amphiphilic mixtures: a self-consistent field theory study

Greenall, Martin J. and Gompper, Gerhard (2011) Bilayers connected by threadlike micelles in amphiphilic mixtures: a self-consistent field theory study. Langmuir, 27 (7). pp. 3416-3423. ISSN 0743-7463

Full content URL: http://dx.doi.org/10.1021/la200138b

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Bilayers connected by threadlike micelles in amphiphilic mixtures: a self-consistent field theory study
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Abstract

Binary mixtures of amphiphiles in solution can self-assemble into a wide range of structures when the two species individually form aggregates of different curvatures. A specific example of this is seen in solutions of lipid mixtures where the two species form lamellar structures and spherical micelles, respectively. Here, vesicles connected by threadlike micelles can form in a narrow concentration range of the sphere-forming lipid. We present a study of these structures based on self-consistent field theory (SCFT), a coarse-grained model of amphiphiles. First, we show that the addition of sphere-forming lipid to a solution of lamella-former can lower the free energy of cylindrical, threadlike micelles and hence encourage their formation. Next, we demonstrate the coupling between composition and curvature; specifically, that increasing the concentration of sphere-former in a system of two bilayers connected by a thread leads to a transfer of amphiphile to the thread. We further show that the two species are segregated within the structure, with the concentration of sphere-former being significantly higher in the thread. Finally, the addition of larger amounts of sphere-former is found to destabilize the junctions linking the bilayers to the cylindrical micelle, leading to a breakdown of the connected structures. The degree of segregation of the amphiphiles and the amount of sphere-former required to destabilize the junctions is shown to be sensitive to the length of the hydrophilic block of the sphere-forming amphiphiles.

Keywords:Polymeric amphiphiles, Self assembly
Subjects:F Physical Sciences > F320 Chemical Physics
G Mathematical and Computer Sciences > G150 Mathematical Modelling
Divisions:College of Science > School of Mathematics and Physics
ID Code:19801
Deposited On:11 Dec 2015 12:06

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