North, S.M. orcid.org/0000-0002-7952-4442 and Armes, S.P. orcid.org/0000-0002-8289-6351 (2021) Aqueous one-pot synthesis of well-defined zwitterionic diblock copolymers by RAFT polymerization : an efficient and environmentally-friendly route to a useful dispersant for aqueous pigments. Green Chemistry, 23 (3). pp. 1248-1258. ISSN 1463-9262
Abstract
Various examples of well-defined zwitterionic diblock copolymers have been reported in the literature. However, synthetic routes to such copolymers have almost invariably involved protecting group chemistry and/or multi-step syntheses. Herein we use reversible addition–fragmentation chain transfer (RAFT) polymerization to develop an atom-efficient, wholly aqueous one-pot synthesis of zwitterionic diblock copolymers comprising anionic methacrylic acid (MAA) and cationic 2-(dimethylamino)ethyl methacrylate (DMA) repeat units. Empirically, we find that polymerizing DMA first leads to a more well-defined block architecture and a narrower molecular weight distribution as judged by 1H NMR spectroscopy and gel permeation chromatography, respectively. Aqueous electrophoresis studies indicate that the isoelectric point (IEP) exhibited by such zwitterionic diblock copolymers in aqueous solution can be tuned by varying the relative proportions of the anionic and cationic comonomers. The convenient removal of trithiocarbonate-based RAFT end-groups can be achieved using aqueous hydrazine, with subsequent macroscopic precipitation of the crude zwitterionic diblock copolymer at its IEP facilitating a highly convenient wholly aqueous work-up. This augurs well for potential applications of these fascinating materials. In this context, we show that such zwitterionic diblock copolymers serve as highly effective dispersants for nano-sized transparent yellow iron oxide nanoparticles, a notoriously problematic aqueous pigment.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 The Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (http://creativecommons.org/licenses/by/3.0/). |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) |
Funding Information: | Funder Grant number Engineering and Physical Science Research Council EP/R003009/1; EP/L016281/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 12 Mar 2021 14:34 |
Last Modified: | 12 Mar 2021 14:34 |
Status: | Published |
Publisher: | Royal Society of Chemistry (RSC) |
Refereed: | Yes |
Identification Number: | 10.1039/d0gc04271d |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:171719 |