Lovett, JR, Warren, NJ orcid.org/0000-0002-8298-1417, Ratcliffe, LPD et al. (2 more authors) (2015) pH-Responsive Non-Ionic Diblock Copolymers: Ionization of Carboxylic Acid End-Groups Induces an Order–Order Morphological Transition. Angewandte Chemie International Edition, 54 (4). pp. 1279-1283. ISSN 1433-7851
Abstract
A carboxylic acid based reversible additionfragmentation transfer (RAFT) agent is used to prepare gels composed of worm-like diblock copolymers using two non-ionic monomers, glycerol monomethacrylate (GMA) and 2-hydroxypropyl methacrylate (HPMA). Ionization of the carboxylic acid end-group on the PGMA stabilizer block induces a worm-to-sphere transition, which in turn causes immediate degelation. This morphological transition is fully reversible as determined by TEM and rheology studies and occurs because of a subtle change in the packing parameter for the copolymer chains. A control experiment where the methyl ester derivative of the RAFT agent is used to prepare the same diblock copolymer confirms that no pH-responsive behavior occurs in this case. This end-group ionization approach is important for the design of new pH-responsive copolymer nano-objects as, unlike polyacids or polybases, only a minimal amount of added base (or acid) is required to drive the morphological transition.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2014 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. |
Keywords: | block copolymers; morphological transitions; nanoparticles; RAFT polymerization; self-assembly |
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: | 07 Oct 2016 10:18 |
Last Modified: | 07 Oct 2016 10:18 |
Published Version: | http://dx.doi.org/10.1002/anie.201409799 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/anie.201409799 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:103574 |