Patel, Anisha, Maitland, Georgia L., Liarou, Evelina, Topham, Paul D. and Derry, Matthew J. (2025). Transparent diblock copolymer nanoparticle dispersions via efficient RAFT emulsion polymerisation in ionic liquid. Polymer Chemistry, 16 (23), pp. 2767-2777.
Abstract
We report the first reversible addition–fragmentation chain transfer polymerisation-induced self-assembly (RAFT-PISA) in ionic liquid (IL) that proceeds under emulsion conditions. Moreover, this formulation exploits refractive index contrast matching to generate highly transparent nanoparticle dispersions. Specifically, 1-ethyl-3-methyl-imidazolium ethylsulfate, [EMIM][EtOSO3], was used as the solvent for the chain extension of poly(2-hydroxyethyl methacrylate) (PHEMA) macromolecular chain transfer agents (macro-CTAs) using n-butyl methacrylate (BuMA) via RAFT emulsion polymerisation. Two series of PHEMAx-b-PBuMAy diblock copolymers with target PBuMA degrees of polymerisation (DPs) varying from 50 to 1000 were synthesised using either a PHEMA21 or PHEMA77 macro-CTA. All resulting nanoparticle dispersions yielded highly transparent dispersions, even when nanoparticle diameters exceeded 100 nm, due to the closely matched refractive index values of the [EMIM][EtOSO3] solvent and PBuMA nanoparticle core. Detailed analysis using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) confirmed the presence of spherical nanoparticles. Furthermore, the synthesis of PHEMA-b-PBuMA via this new PISA formulation was directly compared to equivalent block copolymer syntheses conducted in N, N-dimethylformamide (DMF) or ethanol/water mixtures. It was found that syntheses conducted in [EMIM][EtOSO3] resulted in the highest monomer conversions (up to >99%) and lowest dispersity (ĐM) values (as low as 1.16) in the shortest reaction times (2 hours) compared to the other solvent systems. This work demonstrates the use of ILs as a more sustainable and effective solvent for RAFT–PISA via the development of the first emulsion PISA formulation in IL.
Publication DOI: | https://doi.org/10.1039/d5py00076a |
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Divisions: | College of Engineering & Physical Sciences Aston University (General) |
Funding Information: | M. J. D. wishes to thank EPSRC for funding (grant number EP/Y005309/1) and for providing a DTP studentship for A. P. (EPSRC DTP 2020\u20132021, Aston University, Grant Ref: EP/T518128/1). The Aston Institute for Membrane Excellence (AIME) is funded by UKR |
Additional Information: | Copyright © The Royal Society of Chemistry 2025. Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. |
Publication ISSN: | 1759-9962 |
Data Access Statement: | Additional data to support this article, including polymer and nanoparticle characterisation data, UV-vis measurements, small-angle X-ray scattering data and models and transmission electron microscopy images, have been included as part of the ESI. |
Last Modified: | 02 Jul 2025 16:41 |
Date Deposited: | 23 May 2025 09:44 |
Full Text Link: | |
Related URLs: |
https://pubs.rs ... 5/py/d5py00076a
(Publisher URL) http://www.scop ... tnerID=8YFLogxK (Scopus URL) |
PURE Output Type: | Article |
Published Date: | 2025-06-21 |
Published Online Date: | 2025-05-14 |
Accepted Date: | 2025-05-13 |
Authors: |
Patel, Anisha
Maitland, Georgia L. Liarou, Evelina Topham, Paul D. ( ![]() Derry, Matthew J. ( ![]() |