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Double-network hydrogels improve pH-switchable adhesion

Lookup NU author(s): Professor Mark GeogheganORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2016 The Royal Society of Chemistry.For environmentally-switchable adhesive systems to be reused repeatedly, the adhesive strength must not deteriorate after each adhesion cycle. An important criterion to achieve this goal is that the integrity of the interface must be retained after each adhesion cycle. Furthermore, in order to have practical benefits, reversing the adhesion must be a relatively rapid process. Here, a double-network hydrogel of poly(methacrylic acid) and poly[oligo(ethylene glycol)methyl ether methacrylate] is shown to undergo adhesive failure during pH-switchable adhesion with a grafted (brush) layer of polycationic poly[2-(diethyl amino)ethyl methacrylate], and can be reused at least seven times. The surfaces are attached at pH 6 and detached at pH 1. A single-network hydrogel of poly(methacrylic acid), also exhibits pH-switchable adhesion with poly[2-(diethyl amino)ethyl methacrylate] but cohesive failure leads to an accumulation of the hydrogel on the brush surface and the hydrogel can only be reused at different parts of that surface. Even without an environmental stimulus (i.e. attaching and detaching at pH 6), the double-network hydrogel can be used up to three times at the same point on the brush surface. The single-network hydrogel cannot be reused under such circumstances. Finally, the time taken for the reuse of the double-network hydrogel is relatively rapid, taking no more than an hour to reverse the adhesion.

Publication metadata

Author(s): Alfhaid L, Seddon WD, Williams NH, Geoghegan M

Publication type: Article

Publication status: Published

Journal: Soft Matter

Year: 2016

Volume: 12

Issue: 22

Pages: 5022-5028

Online publication date: 10/05/2017

Acceptance date: 03/05/2016

Date deposited: 19/12/2019

ISSN (print): 1744-683X

ISSN (electronic): 1744-6848

Publisher: Royal Society of Chemistry


DOI: 10.1039/c6sm00656f


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