Photo-Responsive Hydrogels with Enhanced Volume Changes due to Local pH alterations
Refereed Conference Meeting Proceeding
Photo-responsive hydrogels of varying compositions containing spiropyran photochromic units have been widely studied in recent years due to their many potential applications, including photo-actuated micro-valves for microfluidic devices [1,2]. In this study two hydrogel formulations were employed to produce reversible photo-responsive hydrogel actuators operative in neutral pH. Both compositions contain the photochromic unit spiropyran acrylate (SP) and acrylic acid (AA) copolymerised in the main polymer backbone, together with N-isopropylacrylamide (NIPAAm) or acrylamide (AAm), respectively. At neutral pH, the AA comonomer dissociates to the acrylate anion (A-) and the proton transfers to the SP unit to give the more hydrophilic protonated merocyanine (MC-H+) form, which triggers water uptake and hydrogel expansion. Under white light irradiation, the MC-H+ reverts to the more hydrophobic SP isomer, with simultaneous reformation of acrylic acid, and hydrogel contraction.
Analytical and Nanoanalytical Methods for Biomedical and Environmental Sciences (IC-ANMBES 2016)
Proceedings of Analytical and Nanoanalytical Methods for Biomedical and Environmental Sciences (IC-ANMBES 2016)
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Dublin City University (DCU)
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