Controlling the Self-Assembly of Binary Copolymer Mixtures in Solution through Molecular Architecture

Greenall, Martin J.; Schuetz, Peter; Furzeland, Steve; Atkins, Derek; Buzza, D. Martin A.; Butler, Michael F.; McLeish, Tom C.B.

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.

Citation

Greenall, M. J., Schuetz, P., Furzeland, S., Atkins, D., Buzza, D. M. A., Butler, M. F., & McLeish, T. C. (2011). Controlling the Self-Assembly of Binary Copolymer Mixtures in Solution through Molecular Architecture. Macromolecules, 44(13), 5510-5519. https://doi.org/10.1021/ma2008546

• Journal Article Type: Article
• Publication Date: Jul 1, 2011
• Deposit Date: Nov 1, 2011
• Publicly Available Date: Jan 23, 2013
• Journal: Macromolecules
• Print ISSN: 0024-9297
• Electronic ISSN: 1520-5835
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 44
• Issue: 13
• Pages: 5510-5519
• DOI: https://doi.org/10.1021/ma2008546
• Public URL: https://durham-repository.worktribe.com/output/1526052