- Title
- Underscreening in concentrated electrolytes: re-entrant swelling in polyelectrolyte brushes
- Creator
- Robertson, Hayden; Elliott, Gareth R.; Nelson, Andrew R. J.; Le Brun, Anton P.; Webber, Grant B.; Prescott, Stuart W.; Craig, Vincent S. J.; Wanless, Erica J.; Willott, Joshua D.
- Relation
- ARC.DP190100788 http://purl.org/au-research/grants/arc/DP190100788
- Relation
- Physical Chemistry Chemical Physics Vol. 25, p. 24770-24782
- Publisher Link
- http://dx.doi.org/10.1039/d3cp02206d
- Publisher
- Royal Society of Chemistry
- Resource Type
- journal article
- Date
- 2023
- Description
- Hypersaline environments are ubiquitous in nature and are found in myriad technological processes. Recent empirical studies have revealed a significant discrepancy between predicted and observed screening lengths at high salt concentrations, a phenomenon referred to as underscreening. Herein we investigate underscreening using a cationic polyelectrolyte brush as an exemplar. Poly(2-(methacryloyloxy)ethyl)trimethylammonium (PMETAC) brushes were synthesised and their internal structural changes and swelling response was monitored with neutron reflectometry and spectroscopic ellipsometry. Both techniques revealed a monotonic brush collapse as the concentration of symmetric monovalent electrolyte increased. However, a non-monotonic change in brush thickness was observed in all multivalent electrolytes at higher concentrations, known as re-entrant swelling; indicative of underscreening. For all electrolytes, numerical self-consistent field theory predictions align with experimental studies in the low-to-moderate salt concentration regions. Analysis suggests that the classical theory of electrolytes is insufficient to describe the screening lengths observed at high salt concentrations and that the re-entrant polyelectrolyte brush swelling seen herein is consistent with the so-called regular underscreening phenomenon.
- Subject
- underscreening; electrolytes; polyelectrolyte brushes; Poly(2-(methacryl- oyloxy)ethyl)trimethylammonium (PMETAC)
- Identifier
- http://hdl.handle.net/1959.13/1486868
- Identifier
- uon:51979
- Identifier
- ISSN:1463-9076
- Rights
- © 2023 The Authors. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence (https://creativecommons.org/licenses/by-nc/3.0/).
- Language
- eng
- Full Text
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