Block copolymer synthesis in ionic liquid via polymerisation-induced self-assembly: A convenient route to gel electrolytes

Georgia Lucy l Maitland, Mingyu Liu, Thomas Neal, James Hammerton, Yisong Han, Stephen David Worrall, Paul d. Topham, Matthew j Derry*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We report for the first time a reversible addition–fragmentation chain transfer polymerisation-induced self-assembly (RAFT-PISA) formulation in ionic liquid (IL) that yields worm gels. A series of poly(2-hydroxyethyl methacrylate)-b-poly(benzyl methacrylate) (PHEMA-b-PBzMA) block copolymer nanoparticles were synthesised via RAFT dispersion polymerisation of benzyl methacrylate in the hydrophilic IL 1-ethyl-3-methyl imidazolium dicyanamide, [EMIM][DCA]. This RAFT-PISA formulation can be controlled to afford spherical, worm-like and vesicular nano-objects, with free-standing gels being obtained over a broad range of PBzMA core-forming degrees of polymerisation (DPs). High monomer conversions (≥96%) were obtained within 2 hours for all PISA syntheses as determined by 1H NMR spectroscopy, and good control over molar mass was confirmed by gel permeation chromatography (GPC). Nanoparticle morphologies were identified using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), and further detailed characterisation was conducted to monitor rheological, electrochemical and thermal characteristics of the nanoparticle dispersions to assess their potential in future electronic applications. Most importantly, this new PISA formulation in IL facilitates the in situ formation of worm ionogel electrolyte materials at copolymer concentrations >4% w/w via efficient and convenient synthesis routes without the need for organic co-solvents or post-polymerisation processing/purification. Moreover, we demonstrate that the worm ionogels developed in this work exhibit comparable electrochemical properties and thermal stability to that of the IL alone, showcasing their potential as gel electrolytes.
Original languageEnglish
JournalChemical Science
Early online date13 Feb 2024
DOIs
Publication statusE-pub ahead of print - 13 Feb 2024

Data Access Statement

Data for this paper, including polymer and nanoparticle characterisation data, small-angle X-ray scattering fitting and models, oscillatory rheology data and electrochemical impedance spectroscopy data, are available in the ESI

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