- Title
- Combined experimental and theoretical study of weak polyelectrolyte brushes in salt mixtures
- Creator
- Willott, Joshua D.; Humphreys, Ben A.; Webber, Grant B.; Wanless, Erica J.; de Vos, Wiebe M.
- Relation
- Langmuir Vol. 35, Issue 7, p. 2709-2718
- Publisher Link
- http://dx.doi.org/10.1021/acs.langmuir.8b03838
- Publisher
- American Chemical Society
- Resource Type
- journal article
- Date
- 2019
- Description
- The swelling behavior of a hydrophobic poly(2diisopropylamino)ethyl methacrylate (PDPA) brush immersed in aqueous solutions of single and mixed salts has been investigated using ellipsometry and numerical self-consistent field (nSCF) theory. As a function of solution ionic strength, the osmotic and salted brush regimes of weak polyelectrolyte brushes as well as substantial specific anion effects in the presence of K⁺ salts of Cl⁻, NO₃⁻, and SCN⁻ are found. For solutions containing mixtures of NO₃⁻ and Cl⁻, the brush swelling is the same as one would expect on the basis of the concentration-weighted average of the brush behavior in the single salt solutions. However, in mixtures of SCN⁻ and Cl⁻, the swelling response is more complicated and substantial divergence from ideal behavior is observed. Mean-field theory shows excellent qualitative agreement with the ellipsometry findings. nSCF reveals that for the SCN⁻/Cl⁻ cases the swelling behavior of the PDPA brush most likely arises from the predominant localization of the weakly hydrated SCN⁻ within the brush compared to the more strongly hydrated Cl⁻.
- Subject
- weak polyelectrolyte brushes; salt mixtures; hydrophobic poly(2diisopropylamino)ethyl methacrylate (PDPA); field theory
- Identifier
- http://hdl.handle.net/1959.13/1401136
- Identifier
- uon:34874
- Identifier
- ISSN:0743-7463
- Rights
- This is an open access article published under a Creative Commons Non-Commercial No Derivative Works (CC-BY-NC-ND) Attribution License, which permits copying and redistribution of the article, and creation of adaptations, all for non-commercial purposes.
- Language
- eng
- Full Text
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