Lovett, J.R., Ratcliffe, L.P.D. orcid.org/0000-0002-3488-6589, Warren, N.J. et al. (4 more authors) (2016) A Robust Cross-Linking Strategy for Block Copolymer Worms Prepared via Polymerization-Induced Self-Assembly. Macromolecules, 49 (8). pp. 2928-2941. ISSN 0024-9297
Abstract
A poly(glycerol monomethacrylate) (PGMA) chain transfer agent is chain-extended by reversible addition–fragmentation chain transfer (RAFT) statistical copolymerization of 2-hydroxypropyl methacrylate (HPMA) with glycidyl methacrylate (GlyMA) in concentrated aqueous solution via polymerization-induced self-assembly (PISA). A series of five free-standing worm gels is prepared by fixing the overall degree of polymerization of the core-forming block at 144 while varying its GlyMA content from 0 to 20 mol %. 1H NMR kinetics indicated that GlyMA is consumed much faster than HPMA, producing a GlyMA-rich sequence close to the PGMA stabilizer block. Temperature-dependent oscillatory rheological studies indicate that increasing the GlyMA content leads to progressively less thermoresponsive worm gels, with no degelation on cooling being observed for worms containing 20 mol % GlyMA. The epoxy groups in the GlyMA residues can be ring-opened using 3-aminopropyltriethoxysilane (APTES) in order to prepare core cross-linked worms via hydrolysis-condensation with the siloxane groups and/or hydroxyl groups on the HPMA residues. Perhaps surprisingly, 1H NMR analysis indicates that the epoxy–amine reaction and the intermolecular cross-linking occur on similar time scales. Cross-linking leads to stiffer worm gels that do not undergo degelation upon cooling. Dynamic light scattering studies and TEM analyses conducted on linear worms exposed to either methanol (a good solvent for both blocks) or anionic surfactant result in immediate worm dissociation. In contrast, cross-linked worms remain intact under such conditions, provided that the worm cores comprise at least 10 mol % GlyMA.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 American Chemical Society. ACS AuthorChoice - This is an open access article published under a Creative Commons Attribution (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
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: | 27 Jun 2016 08:51 |
Last Modified: | 27 Jun 2016 08:51 |
Published Version: | http://dx.doi.org/10.1021/acs.macromol.6b00422 |
Status: | Published |
Publisher: | ACS |
Refereed: | Yes |
Identification Number: | 10.1021/acs.macromol.6b00422 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:101406 |