| Photoisomerizable and Thermoresponsive N-isopropylacrylamide-Surfmer Copolymer Hydrogels Prepared upon Electrostatic Self-Assembly of an Azobenzene Bolaamphiphile. | |
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MedLine Citation:
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PMID: 23355321 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Photoreactive and thermoresponsive N-isopropylacrylamide (NIPAM)-surfmer copolymer hydrogels containing 4,4'-di(6-sulfato-hexyloxy)azobenzene (DSHA) dianions are described. The functional hydrogels are obtained in a two steps. First a micellar aqueous solution of (11-(acryloyloxy)undecyl)trimethylammonium bromide (AUTMAB) and NIPAM is exposed to (60) Co-gamma irradiation, and a thermoresponsive copolymer gel is obtained. Second, DSHA is included by shrinking the gel at 50 °C and subsequent reswelling in an aqueous solution of DSHA disodium salt at 20 °C. Reswelling is accompanied by electrostatic adsorption of DSHA dianions at the positively charged AUTMAB headgroups replacing the bromide ions. Gels containing trans-DSHA are transparent yellow at room temperature (λ(max) = 370 nm), while gels containing cis-rich DSHA are orange (λ(max) = 460 and 330 nm). Energy dispersive X-ray measurements indicate that 41% of the bromide ions are exchanged if trans-DSHA is used for adsorption, and only 7.5% if cis-DSHA is used. The incorporation of DSHA lowers the lower critical solution temperature (LCST) from 34 to 32 °C. Below the LCST, DSHA can be switched from the trans- to the cis-rich state and vice versa upon irradiation with UV (λ = 366 nm) or visible light (λ ≥ 450 nm). Above the LCST no photoreaction takes place. |
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Authors:
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Tatjana Friedrich; Tamara Mielke; Monika Domogalla; Maria Hentschel; Katharina Kraus; Bernd Tieke |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2013-1-28 |
Journal Detail:
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Title: Macromolecular rapid communications Volume: - ISSN: 1521-3927 ISO Abbreviation: Macromol Rapid Commun Publication Date: 2013 Jan |
Date Detail:
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Created Date: 2013-1-28 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9888239 Medline TA: Macromol Rapid Commun Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Affiliation:
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Department of Chemistry, University of Cologne, D-50939 Cologne, Germany. |
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Descriptor/Qualifier:
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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