Intelligent gels and cryogels with embedded emulsions of various oils

Abstract

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 threedimensional 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 À15 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.

Encapsulated Microstructures of Beneficial Functional Lipids and Their Applications in Foods and Biomedicines

“…123 Komarova et al prepared a thermoresponsive gelatin with an O/W emulsions of olive, peanut, and linseed oil. 124 The polymer hydrogel remained chemically stable in freezing conditions, but it dissolved and released the oil at the mammal body temperature. Yang's group developed O/W high internal phase pickering emulsion stabilizer, which enabled gelatin with soybean oil as the dispersed phase to have unique temperature response capabilities 125 (Figure 8C).…”

Cryostructuring of Polymeric Systems. 55. Retrospective View on the More than 40 Years of Studies Performed in the A.N.Nesmeyanov Institute of Organoelement Compounds with Respect of the Cryostructuring Processes in Polymeric Systems

“…Such materials were able to squeeze the oil phase through the system of the interconnected gross open pores upon the volumetric shrinking of the polymeric phase in response to the temperature exceeding the LCST point. In contrast, the same, with respect to the chemical composition, oil-filled microporous hydrogels synthesized at a room temperature were unable to perform similar squeezing of the oil phase, though the heating-induced collapse of the matrix occurred, and this process “conserved” the hydrophobic liquid inside the bulk of the shrunk composite rather than caused the oil plug flow [ 241 , 242 ].…”

Transport in droplet-hydrogel composites: response to external stimuli

“…As a new type of hydrogel-based composites, emulsion-filled gels (droplet-hydrogel composites) are polymer assemblies that integrate dispersed oil droplets within a water-saturated hydrogel phase. This type of hydrogel-based composites have been developed as a new class of materials for drug delivery, food sciences, and responsive materials [15][16][17]. The rheological and lubrication properties of these composites have been observed to depend on the properties of the hydrogel and droplets, the droplet concentration, and the droplet-hydrogel interactions [18,19].…”