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Porous self-protonating spiropyran-based NIPAAm gels with improved reswelling kinetics

Ziółkowski, Bartosz and Florea, Larisa and Theobald, Jannick and Benito-Lopez, Fernando and Diamond, Dermot (2016) Porous self-protonating spiropyran-based NIPAAm gels with improved reswelling kinetics. Journal of Materials Science, 51 (3). pp. 1392-1399. ISSN 1573-4803

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This study focuses on improving the speed of actuation of poly(N-isopropylacrylamide)-based photoresponsive gels containing copolymerised spiropyran as the photoswitch and acrylic acid as the proton source. The improvement is realised by introducing pores into the material. For this purpose, polyethylene glycol (PEG) of two molecular weights (2,000 and 20,000 g mol-1) has been used as the porophore in the polymerisation mixture. Upon removal of the PEG porophore post polymerisation, hydrogels of different pore sizes were obtained. This impacts the diffusion of water molecules moving in/out of the hydrogel matrix, thus improving the swelling and shrinking kinetics of the hydrogel due to reduction of the average diffusion pathlength. Most significant improvement was observed in the re-swelling step and is demonstrated with optical microscopy combined with kinetic ultraviolet–visible spectroscopy (UV-Vis) analysis. Scanning Electron Microscopy reveals the PEG-induced pores to be in the range of 0.1 - 2 μm. Moreover, the mechanical stability of the gels is confirmed with rheometry. Lastly, the presented photoresponsive porous gels exhibit an order of magnitude faster reswelling rate compared to the non-PEG produced control sample.

Item Type:Article (Published)
Uncontrolled Keywords:Stimulus responsive; Gels; Spiropyran; Photoresponsive; Porosity
Subjects:Physical Sciences > Photochemistry
Physical Sciences > Organic chemistry
Physical Sciences > Chemistry
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Chemical Sciences
Research Initiatives and Centres > INSIGHT Centre for Data Analytics
Research Initiatives and Centres > National Centre for Sensor Research (NCSR)
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Copyright Information:© 2016 Springer. The original publication is available at
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 3.0 License. View License
Funders:Science Foundation Ireland under the Insight initiative, grant SFI/12/RC/2289, EU Framework 7 project “ATWARM” (Marie Curie ITN, No. 238273, FBL acknowledges the Ramón y Cajal Programme (Ministerio de Economía y Competitividad), Spain and the European Union´s Seventh Framework Programme (FP7) for Research, Technological Development and Demonstration under grant agreement no. 604241
ID Code:21285
Deposited On:26 Jul 2016 13:43 by Larisa Florea. Last Modified 01 Feb 2017 01:02

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