Thompson, KL, Mable, CJ, Cockram, A et al. (5 more authors) (2014) Are block copolymer worms more effective Pickering emulsifiers than block copolymer spheres? Soft Matter, 10 (43). pp. 8615-8626. ISSN 1744-683X
Abstract
RAFT-mediated polymerisation-induced self-assembly (PISA) is used to prepare six types of amphiphilic block copolymer nanoparticles which were subsequently evaluated as putative Pickering emulsifiers for the stabilisation of n-dodecane-in-water emulsions. It was found that linear poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) (PGMA-PHPMA) diblock copolymer spheres and worms do not survive the high shear homogenisation conditions used for emulsification. Stable emulsions are obtained, but the copolymer acts as a polymeric surfactant; individual chains rather than particles are adsorbed at the oil-water interface. Particle dissociation during emulsification is attributed to the weakly hydrophobic character of the PHPMA block. Covalent stabilisation of these copolymer spheres or worms can be readily achieved by addition of ethylene glycol dimethacrylate (EGDMA) during the PISA synthesis. TEM studies confirm that the resulting cross-linked spherical or worm-like nanoparticles survive emulsification and produce genuine Pickering emulsions. Alternatively, stabilisation can be achieved by either replacing or supplementing the PHPMA block with the more hydrophobic poly(benzyl methacrylate) (PBzMA). The resulting linear spheres or worms also survive emulsification and produce stable n-dodecane-in-water Pickering emulsions. The intrinsic advantages of anisotropic worms over isotropic spheres for the preparation of Pickering emulsions are highlighted. The former particles are more strongly adsorbed at similar efficiencies compared to spheres and also enable smaller oil droplets to be produced for a given copolymer concentration. The scalable nature of PISA formulations augurs well for potential applications of anisotropic block copolymer nanoparticles as Pickering emulsifiers.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Royal Society of Chemistry 2014. This open access article is licensed under a Creative Commons Attribution 3.0 Unported Licence. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 17 Aug 2016 15:10 |
Last Modified: | 17 Aug 2016 15:10 |
Published Version: | http://dx.doi.org/10.1039/C4SM01724B |
Status: | Published |
Publisher: | Royal Society of Chemistry |
Identification Number: | 10.1039/c4sm01724b |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:103578 |