Authors
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Rueda, J.C. ; Campos, E. ; Komber, H. ; Zschoche, St. ; Häußler, L. ; Voit, B.
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Title
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Synthesis and characterization of new pH- and thermo-responsive hydrogels based on N-isopropylacrylamide and 2-oxazolines
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Date
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01.03.2014
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Number
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38203
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Abstract
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New pH- and thermo-responsive hydrogels (HG) were synthesized by free radical polymerization of N-isopropylacrylamide and a macromonomer, which was a hydrolyzed random copolymer of 2-carboxyethyl- and 2-methyl-2-oxazoline, using a bisacrylamide as crosslinker. The polymerization was carried out in a mixture of water and ethanol at room temperature and was initiated by ammonium peroxodisulfate. The HG showed conformational transitions with variation of temperature and/or pH-value and as a function of hydrogel composition. This property was shown macroscopically as hydrogel contraction or expansion. The HG structures were characterized by high-resolution magic angle spinning (HRMAS) NMR spectroscopy. The thermal properties, in particular the lower critical solution temperatures, were determined by temperature-dependent HRMAS NMR measurements and differential scanning calorimetry. The pH responsibility was determined by swelling experiments in water at different pH values.
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Publisher
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Designed Monomers and Polymers
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Wikidata
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Citation
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Designed Monomers and Polymers 17 (2014) 208-216
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DOI
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https://doi.org/10.1080/15685551.2013.840471
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Tags
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hydrogels stimuli-sensitive polymers networks graft copolymers macromonomers swelling graft-copolymers poly(n-isopropylacrylamide) polymerization temperature
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