Controlling the self-assembly of binary copolymer mixtures in solution through molecular architecture

Greenall, Martin J. and Schuetz, Peter and Furzeland, Steve and Atkins, Derek and Buzza, D. Martin A. and Butler, Michael F. and McLeish, Tom C. B. (2011) Controlling the self-assembly of binary copolymer mixtures in solution through molecular architecture. Macromolecules, 44 (13). pp. 5510-5519. ISSN 0024-9297

Full content URL: http://dx.doi.org/10.1021/ma2008546

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Controlling the self-assembly of binary copolymer mixtures in solution through molecular architecture
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Abstract

We present a combined experimental and theoretical study on the role of copolymer architecture in the self-assembly of binary PEO-PCL mixtures in water-THF and show that altering the chain geometry and composition of the copolymers can control the form of the self-assembled structures and lead to the formation of novel aggregates. First, using transmission electron microscopy and turbidity measurements, we study a mixture of sphere-forming and lamella-forming PEO-PCL copolymers and show that increasing the molecular weight of the lamella-former at a constant ratio of its hydrophilic and hydrophobic components leads to the formation of highly curved structures even at low sphere-former concentrations. This result is explained using a simple argument based on the effective volumes of the two sections of the diblock and is reproduced in a coarse-grained mean-field model: self-consistent field theory (SCFT). Using further SCFT calculations, we study the distribution of the two copolymer species within the individual aggregates and discuss how this affects the self-assembled structures. We also investigate a binary mixture of lamella-formers of different molecular weights and find that this system forms vesicles with a wall thickness intermediate to those of the vesicles formed by the two copolymers individually. This result is also reproduced using SCFT. Finally, a mixture of sphere-former and a copolymer with a large hydrophobic block is shown to form a range of structures, including novel elongated vesicles.

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:19800
Deposited On:11 Dec 2015 12:00

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