Microfibres and macroscopic films from the coordination-driven hierarchical self-assembly of cylindrical micelles.

David J Lunn,Ian Manners,Daniel P Armstrong,Richard J Spontak,Oliver E C Gould,George R Whittell,Paul G Pringle,Kenneth P Mineart,Mitchell A Winnik

doi:10.1038/ncomms12371

David J Lunn, Ian Manners + Show 7 more

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https://doi.org/10.1038/ncomms12371

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Abstract

Anisotropic nanoparticles prepared from block copolymers are of growing importance as building blocks for the creation of synthetic hierarchical materials. However, the assembly of these structural units is generally limited to the use of amphiphilic interactions. Here we report a simple, reversible coordination-driven hierarchical self-assembly strategy for the preparation of micron-scale fibres and macroscopic films based on monodisperse cylindrical block copolymer micelles. Coordination of Pd(0) metal centres to phosphine ligands immobilized within the soluble coronas of block copolymer micelles is found to induce intermicelle crosslinking, affording stable linear fibres comprised of micelle subunits in a staggered arrangement. The mean length of the fibres can be varied by altering the micelle concentration, reaction stoichiometry or aspect ratio of the micelle building blocks. Furthermore, the fibres aggregate on drying to form robust, self-supporting macroscopic micelle-based thin films with useful mechanical properties that are analogous to crosslinked polymer networks, but on a longer length scale.

Highlights

Anisotropic nanoparticles prepared from block copolymers are of growing importance as building blocks for the creation of synthetic hierarchical materials
Radical hydrophosphination under photolytic conditions was used to functionalize a percentage of the vinyl groups with diphenylphosphine, affording BCPP (Fig. 1, Supplementary Fig. 1 and Supplementary Table 1) with 35% -PPh2 incorporation based on analysis by proton nuclear magnetic resonance (1H NMR) spectroscopy
Monodisperse cylindrical micelles were prepared from BCPP by living crystallization-driven self-assembly (CDSA) utilizing the crystalline nature of the PFS core-forming block[38,39,40,41]

Summary

Introduction

Anisotropic nanoparticles prepared from block copolymers are of growing importance as building blocks for the creation of synthetic hierarchical materials. We report a simple, reversible coordination-driven hierarchical self-assembly strategy for the preparation of micron-scale fibres and macroscopic films based on monodisperse cylindrical block copolymer micelles. This additional homopolymer functions as a ‘glue’ between micelle subunits, affording short, polydisperse, linear and branched chains of micelles[45] Despite these advances, methods for the self-assembly of anisotropic BCP nanoparticles are generally limited to the exploitation of building-block amphiphilicity[46]. We demonstrate the reversible coordination-driven hierarchical self-assembly of monodisperse cylindrical BCP micelles, affording a series of complex superstructures and stable linear fibres that can be further processed into macroscopic micelle-based thin films

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Conclusion