Autonomous Volume Transitions of a Polybase Triblock Copolymer Gel in a Chemically Driven pH-Oscillator


A pH‐responsive ABA triblock copolymer, comprising poly(methyl methacrylate)‐block‐poly(2‐(diethylamino)ethyl methacrylate)‐block‐poly(methyl methacrylate) [PMMA‐b‐PDEA‐b‐PMMA], has been cast into thin films with a well‐defined microstructure. Small Angle X‐ray Scattering (SAXS) and Atomic Force Microscopy (AFM) studies confirm that this copolymer forms a hydrogel consisting of PMMA spheres embedded within a polybase PDEA matrix, with the PMMA domains acting as physical cross‐links. The hydrogel has a pH‐reversible coil‐globule transition at around pH 4.5. This responsive physical property was exploited by immersing a sample of copolymer hydrogel in an aqueous solution containing a cyclic pH‐oscillating reaction, whereby the pH was continuously oscillated above and below the transition pH so as to induce autonomous volume transitions. The changes in microscopic and macroscopic length scales correlate closely during (de)swelling cycles, with affine behaviour occurring over five orders of magnitude.

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Divisions: College of Engineering & Physical Sciences > Aston Institute of Materials Research (AIMR)
College of Engineering & Physical Sciences
Additional Information: This is the peer reviewed version of the following article: Topham, P. D., Howse, J. R., Crook, C. J., Gleeson, A. J., Bras, W. , Armes, S. P., Jones, R. A. and Ryan, A. J. (2007), Autonomous Volume Transitions of a Polybase Triblock Copolymer Gel in a Chemically Driven pH‐Oscillator. Macromol. Symp., 256: 95-104, which has been published in final form at  This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Publication ISSN: 1521-3900
Last Modified: 13 May 2024 07:21
Date Deposited: 07 Nov 2018 16:27
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Related URLs: http://doi.wile ... /masy.200751011 (Publisher URL)
PURE Output Type: Article
Published Date: 2007-09-25
Authors: Topham, Paul D. (ORCID Profile 0000-0003-4152-6976)
Howse, Jonathan R.
Crook, Colin J.
Gleeson, Anthony J.
Bras, Wim
Armes, Steven P.
Jones, Richard A. L.
Ryan, Anthony J.



Version: Accepted Version

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