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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

The complex formation of organogels based on poly(N-vinylcaprolactam) (PVCa) and organic dyes [5-(4-dimethylaminobenzylidene) rhodanine, α-nitroso-β-naftol, and dithizone] and the properties of the complexes in salt aqueous solutions were studied. PVCa gels absorbed these dyes in organic media (ethanol and chloroform). Our main focus was the behavior of the gel/dye complex immersed in a salt aqueous solution if the dye was the chelating ligand for metal ions. The behavior of the PVCa/dithizone (Dz)/chloroform system was studied in AgNO3 aqueous solutions. The absorption spectra of gel/dye and gel/dye/metal ion systems were investigated. The results obtained indicate that Ag+ ions penetrate the gel phase and that the Dz/silver complexes are indeed formed inside the gel. The dependence of the optical density of the gel/dye/metal ion systems on the AgNO3 concentration was observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3238–3243, 2001

The behavior of slightly crosslinked poly(N-vinylcaprolactam) (PVCa) gels in a CuSO4 solution in water and ethanol was studied. The investigation was carried out for PVCa gels with polymer contents of 4% and 7%. The effective absorption of CuSO4 by PVCa hydrogel accompanied by gel shrinking was observed for the CuSO4 aqueous solution. It was shown that dendrite crystals of CuSO45H2O localized within the gel sample are obtained after placement of gels samples into ethanol. The crystal habit depends on gel concentration. It was found that slightly crosslinked PVCa gels are promising as media for the growth of crystals. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2838–2842, 2001