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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Published with license by Taylor & Francis © 2017 Latifah Alfhaid, Rita La Spina, Michael R. Tomlinson, Amy R. Hall, William D. Seddon, Nicholas H. Williams, Fabrice Cousin, Stanislav Gorb, and Mark Geoghegan.The adhesion between a grafted polyelectrolyte layer (brush) and a gel of an oppositely charged polyelectrolyte has been measured as a function of applied pressure, and the interface has been traced using neutron reflectometry. The interface (in aqueous medium at pH 6) between the (polycationic) brush and the (polyanionic) gel has a limited pressure dependence, with a small amount of deformation of the interface at the brush–gel contact. Brushes with a dry thickness of up to 13 nm exhibit weak adhesion (measured using a mechanical force tester) with an adhesive failure when the gel is detached. Thicker brushes result in the gel exhibiting cohesive failure. Reversing the geometry, whereby a polycationic brush is replaced with a polyanion and the polyanionic gel is replaced with a polycation, reveals that the pH dependence of the adhesion is moderately symmetric about pH 6, but that the maximum force required to separate the polycation gel from the polyanion brush over the range of pH is greater than that for the polycation brush and polyanion gel. The polyanion used is poly(methacrylic acid) (PMAA) and polycations of poly[2-(diethylamino)ethyl methacrylate] (PDEAEMA) and poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) were used.
Author(s): Alfhaid L, La Spina R, Tomlinson MR, Hall AR, Seddon WD, Williams NH, Cousin F, Gorb S, Geoghegan M
Publication type: Article
Publication status: Published
Journal: Journal of Adhesion
Print publication date: 01/01/2018
Online publication date: 06/12/2016
Acceptance date: 24/11/2016
Date deposited: 19/12/2019
ISSN (print): 0021-8464
ISSN (electronic): 1545-5823
Publisher: Taylor and Francis Inc.
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