Dong Q.,Fuyang Normal University |
Dong Q.,Anhui Provincial Key Laboratory for Degradation and Monitoring of the Pollution of the Environment |
Qian M.,Fuyang Normal University |
Qian M.,Anhui Provincial Key Laboratory for Degradation and Monitoring of the Pollution of the Environment |
And 3 more authors.
Journal of Polymer Research | Year: 2016
The phase separation behavior and fluorescence properties of linear PNIPAM with chalcone side groups (PNIPAM-C) in water-cononsolvent systems were studied as a function of solvent composition (x) and temperature. It was found that PNIPAM-C exhibited a single lower critical solution temperature (LCST) in water–methanol, water–acetone, and water–tetrahydrofuran; the addition of organic solvents initially decreased the phase separation temperature and a further addition increased it rapidly. The minimum LCST was −8 °C for the mole fraction of methanol xmethanol ≈ 0.31, 17 °C for xacetone ≈ 0.14, and −2 °C for xtetrahydrofuran ≈ 0.13. However, in water–ethanol solution, a simultaneous LCST and upper critical solution temperature (UCST) existed for lower and higher ethanol concentrations, respectively, and the phase separation temperature decreased drastically with increasing ethanol concentrations. Furthermore, the solvent composition-sensitive and temperature-sensitive fluorescence properties of PNIPAM-C were investigated. The results showed that the fluorescence emission wavelength (λmax) underwent a blue shift and the intensity increased with the addition of a small amount of organic solvent. With further addition of organic solvent, λmax and intensity were almost not changed. However, when the content of organic solvent exceeded a critical value, such as xmethanol > 0.17, λmax blueshifted and the intensity increased with the increase of organic solvent. At low content of organic solvent, λmax decreased greatly and the intensity increased rapidly as the temperature was raised from 20 °C to 50 °C because phase separation occurred when the temperature was elevated. © 2016, Springer Science+Business Media Dordrecht.
Luo C.,Fuyang Teachers College |
Luo C.,Anhui Provincial Key Laboratory for Degradation and Monitoring of the Pollution of the Environment |
Luo C.,Fudan University |
Dong Q.,Fuyang Teachers College |
And 4 more authors.
Chemical Physics Letters | Year: 2016
Two types of thermosensitive polymer-modified gold nanoparticles (GNPs), P(DMAM-co-MADMAC)-modified GNPs (GNPs@PDM) and P(NIPAM-co-MADMAC)-modified GNPs (GNPs@PNM), are fabricated by the “grafting through” polymerization technique. The as-prepared GNPs are characterized by UV–vis, TEM, XPS, TGA, FT-IR and 1H NMR spectroscopy. The thermosensitivity and fluorescence of the GNPs are investigated. It is found that all GNPs aqueous solutions but GNPs@PDM1 exhibit thermosensitivity originated from thermosensitive polymer chains and sensitive fluorescence from the dimethylaminochalcone group. The lower critical solution temperature (LCST) of the GNPs decreases with the increasing content of MADMAC unit in the GNPs. The GNPs aqueous solution shows weak fluorescence after the temperature increases from 25 °C to 45 °C, or after β-cyclodextrin (β-CD) is added. Furthermore, it exhibits strong fluorescence when the solvent is changed to ethanol or chloroform, and the fluorescent wavelength undergoes a blue shift from ethanol to chloroform. © 2016 Elsevier B.V.
Liu Z.,Fuyang Normal College |
Liu Z.,Anhui Provincial Key Laboratory for Degradation and Monitoring of the Pollution of the Environment |
Wang W.,Fuyang Normal College |
Xu H.,Fuyang Normal College |
And 4 more authors.
Inorganic Chemistry Communications | Year: 2015
A novelcolorimetric cobalt(II) chemosensor ratiometric and (HL) based on coumarin platform has been synthesized. It displayed a remarkable (44 nm) red-shift in the absorption spectra upon reaction with Co2+, which is easily observed from yellow to red by the naked-eye. Co2+ could be quantitatively detected in the range of 0-10 μM by both normal and ratiometric absorption spectrometry methods. The detection limit of HL for Co2+ detection was as low as 0.31 μM. © 2015 Elsevier B.V.