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.
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.
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|Publisher Web site:||http://dx.doi.org/10.1021/ma2008546|
|Publisher statement:||This document is the Accepted Manuscript version of a Published Work that appeared in final form in Macromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher.|
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|Last Modified:||19 Feb 2013 12:18|
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