Derry, M. J., Mykhaylyk, O. O. and Armes, S. P. (2017) A Vesicle-to-Worm Transition Provides a New High-Temperature Oil Thickening Mechanism. Angewandte Chemie, 129 (7). pp. 1772-1776. ISSN 0044-8249
Abstract
Diblock copolymer vesicles are prepared via RAFT dispersion polymerization directly in mineral oil. Such vesicles undergo a vesicle-to-worm transition on heating to 150 °C, as judged by TEM and SAXS. Variable-temperature 1H NMR spectroscopy indicates that this transition is the result of surface plasticization of the membrane-forming block by hot solvent, effectively increasing the volume fraction of the stabilizer block and so reducing the packing parameter for the copolymer chains. The rheological behavior of a 10 % w/w copolymer dispersion in mineral oil is strongly temperature-dependent: the storage modulus increases by five orders of magnitude on heating above the critical gelation temperature of 135 °C, as the non-interacting vesicles are converted into weakly interacting worms. SAXS studies indicate that, on average, three worms are formed per vesicle. Such vesicle-to-worm transitions offer an interesting new mechanism for the high-temperature thickening of oils.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. https://creativecommons.org/licenses/by/4.0/ |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 03 Apr 2017 15:19 |
Last Modified: | 03 Apr 2017 15:19 |
Published Version: | http://dx.doi.org/10.1002/ange.201609365 |
Status: | Published |
Publisher: | Wiley: 12 months for Gesellschaft Deutscher Chemiker (GDCh) |
Refereed: | Yes |
Identification Number: | 10.1002/ange.201609365 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:114353 |