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Thermo-responsive gels and cryogels with embedded microdroplets of Vaseline, olive, peanut, and linseed oils and their mixtures with hydrophobic dye Sudan 3 have been synthesized and studied. These composite gel matrices were obtained by the three-dimensional copolymerization of N-isopropylacrylamide and N, N'-bis(acryloyl)cystamine in the presence of oil emulsions stabilized with sodium dodecylsulfate or Span 80. Polymerization was performed at room temperature for conventional gels and at −15°C for cryogels. It was shown that all synthesized systems exhibit heat-induced collapse at temperatures higher then 34°C. For conventional gels prepared at room temperature shrinking lasts within 20 to 80 min in accordance with gel composition. No squeezing of oil droplets was observed. In the case of cryogels, shrinking was accompanied by release of oils and response time was significantly shorter, about tens of seconds. Collapse character and release of lipophilic phase did not depend on the chemical nature of oils, dissolved compounds, and surfactant used for emulsion stabilization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 |
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