Novel thermosensitive nanocomposite (NC) hydrogels consisting of organic/inorganic networks are prepared via in situ free radical polymerization of 2‐(2‐methoxyethoxy) ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA) in the presence of inorganic cross‐linker clay in aqueous solution. The obtained clay/P(MEO2MA‐co‐OEGMA) hydrogels exhibit double volume phase transition temperatures, an upper critical solution temperature (UCST), and a lower critical solution temperature (LCST), which can be controlled between 5 and 85 °C by varying the fraction of OEGMA units and the weight percentage of cross‐linker clay. These new types of NC hydrogels with excellent reversible thermosensitivity are promising for temperature‐sensitive applications such as smart optical switches.
To get a multi-responsive polymer hydrogel, metal sensible and acid/base-switchable D-π-A type dye monomer was synthesized first. The synthesized electron donor-π-conjugated-electron acceptor (D-π-A) type dye monomer 3 was investigated with not only the selective Ni2+ and Cu2+ metal ion sensing effects, but also an acid/base unit sensing effects in optical properties with UV-vis absorption and fluorescence emission. A thermo-responsive poly(NIPAM-co-dye) copolymer with D-π-A type dye was prepared by typical radical copolymerization. The LCST behavior was investigated by UV-vis spectroscopy, which allows the measurement of the phase transition from 20 to 50 °C in an aqueous solution. The poly(NIPAM-co-dye) copolymer also exhibited color change when not only Ni2+ or Cu2+ cations were used but also when an acid/base unit was used. The morphology of the internal matrix structure of the poly(NIPAM-co-dye) hydrogel was observed by SEM. 相似文献
Liquid–liquid equilibria of systems water (A) + CiEj surfactant (B) + n-alkane (C) have been modeled by a mass-action law model previously developed and so far successfully applied to a series of binary water + CiEj systems and to the ternary system water + C4E1 + n-dodecane. These calculations provide the basis for the presented modeling. The aqueous systems give information about the association constants and the χAB-parameter of the Flory–Huggins theory and the ternary C4E1-system provides universal temperature functions for the χAC- and the χBC-parameter. The three-phase equilibrium for seven ternary CiEj systems (i = 6–12, j = 3–6) has been calculated by fitting one additional parameter for each of both temperature functions to the characteristic “fish-tail” point. The agreement with the experimental data is reasonably well. For systems with very small three-phase areas the results can considerably be improved by individual temperature functions that incorporate the experimental temperature maximum of the “fish” into the parameter fit. Based on the parameters of the system water + C8E4 + n-C8H18 the “fish-shaped” phase diagram of the system water + C8E4 + n-C14H30 was predicted reasonably well. 相似文献
The phase behavior of a weakly interacting binary system composed of deuterated polystyrene (dPS) and poly(n‐hexyl methacrylate) (PnHMA) was investigated by the turbidity measurement for the binary blend, and by small angle X‐ray scattering (SAXS) and depolarized light scattering for the block copolymers. For the binary dPS/PnHMA blend, a new phase diagram involving both the upper critical solution transition (UCST) and lower critical solution transition (LCST) was observed by the delicate control of molecular weights between dPS and PnHMA. Whereas for the block copolymers such as dPS‐block‐PnHMA and PS‐block‐PnHMA, an order‐to‐disorder transition (ODT) on heating was observed within the experimental temperature range depending on the molecular weight. This coexistence of both a UCST and LCST in the dPS/PnHMA blend consequently represents the experimental evidence that the corresponding (d)PS‐b‐PnHMAs possess not only ODT, but also lower disorder‐to‐order transition (LDOT) character driven by a compressibility difference, although the latter is hindered by thermal degradation.
