Derry, M.J. orcid.org/0000-0001-5010-6725, Mykhaylyk, O.O. and Armes, S.P. orcid.org/0000-0002-8289-6351 (2017) A Vesicle-to-Worm Transition Provides a New High-Temperature Oil Thickening Mechanism. Angewandte Chemie International Edition, 56 (7). pp. 1746-1750. ISSN 1433-7851
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 (1) H 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.
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Copyright, Publisher and Additional Information: | ©2017 The Authors. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. | ||||||
Keywords: | RAFT polymerization; block copolymers; morphology transition; nanoparticles; polymerization-induced self-assembly | ||||||
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Institution: | The University of Sheffield | ||||||
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) | ||||||
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Depositing User: | Symplectic Sheffield | ||||||
Date Deposited: | 17 Jan 2017 13:53 | ||||||
Last Modified: | 06 Jul 2023 13:53 | ||||||
Status: | Published | ||||||
Publisher: | John Wiley & Sons | ||||||
Refereed: | Yes | ||||||
Identification Number: | https://doi.org/10.1002/anie.201609365 | ||||||
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