In-situ microscopic FTIR spectroelectrochemical technique(MFTIRs) was applied to studying the electrochemical oxidation of ascorbic acid(AA) in poly(ethylene glycol)(PEG) paste at a 100 μm diameter Pt disk electrod...In-situ microscopic FTIR spectroelectrochemical technique(MFTIRs) was applied to studying the electrochemical oxidation of ascorbic acid(AA) in poly(ethylene glycol)(PEG) paste at a 100 μm diameter Pt disk electrode. Using this technique, the catalytic ability of cobalt hexacyanoferrate(CoHCF) microcrystalline toward AA oxidation was also studied. It was found that the dispersed CoHCF powder in the PEG paste can generate well shaped thin layer cyclic voltammetric waves with the peak height proportional to the scan rate, corresponding to the Fe centered redox reactions. This oxidation step catalyzed the AA oxidation. Also, this pasted CoHCF powder generated well resolved in situ MFTIRs spectra, by which a chemical interaction between CC bond of AA ring and CoHCF lattice was revealed. A corresponding surface docking mechanism for the catalytic reaction has been proposed.展开更多
Crosslinking is one of the effective routes for improving the orientation stability of poled polymer films. The derivative of polyvinyl alcohol containing 4-nitro-4'-alkoxystilbene and photo-crosslinkable cinnamyl...Crosslinking is one of the effective routes for improving the orientation stability of poled polymer films. The derivative of polyvinyl alcohol containing 4-nitro-4'-alkoxystilbene and photo-crosslinkable cinnamyl groups as side chains has been synthesized. The in-situ simultaneous photo-crosslinking poling of synthesized polymer films has teen performed, The second order nonlinear optical coefficient d(33) of poled film is 11 pm/V. The SHG measurements show that the break-over temperature of SHG signal is raised obviously after irradiation, its orientation stability is doubled as compared with that of non-crosslinking samples.展开更多
Hybrid proton conducting membranes of poly（vinyl alcohol） （PVA） and phosphomolybdic acid （PMA） were prepared by solution casting method. The effect of PMA doping and PVA crosslinking density on the membrane prop...Hybrid proton conducting membranes of poly（vinyl alcohol） （PVA） and phosphomolybdic acid （PMA） were prepared by solution casting method. The effect of PMA doping and PVA crosslinking density on the membrane properties and proton conductivity were investigated. The crosslinking reaction between the hydroxyl group of PVA and the aldehyde group of glutaraldehyde （GA） was characterized by IR spectroscopy. Proton conductivity of the membranes increases with an increase in concentration of the doped PMA and also with an increase in crosslinking density of the membranes. Proton conductivity results indicate that a significant amount of PMA was maintained in the membranes even after several hours of immersion in water. A maximum conductivity of 0.0101 S cm^-1 was obtained for the membrane with 33.3 wt% PMA and crosslinking density of 5.825 mol%. X-ray diffraction studies were carried out to investigate the influence of PMA doping and crosslinking density on the nature of the membranes. These properties make them very good candidates for polymer electrolyte membranes for direct methanol fuel cell application.展开更多
According to the chemical design, electrorheological properties of supramolecular complex from β-cyclodextrin polymer (β -CDP) were discussed. Six supramolecular complexes of β-cyclodextrin polymer with substituted...According to the chemical design, electrorheological properties of supramolecular complex from β-cyclodextrin polymer (β -CDP) were discussed. Six supramolecular complexes of β-cyclodextrin polymer with substituted salicylic acid and 3-hydroxy-2-naphthoic acid were synthesized by the solid-phase self-assembly method, and their component and structure were characterized by NMR, FT-IR, UV-vis and the fluorescence analysis. Then the electrorheological properties of their suspensions in silicone oil were investigated under DC electric fields. It was found that the yield stresses of these supramolecular complex ER fluids were 7.3–9.8 kPa at 4 kV/mm in DC electric field, which were enhanced by 34%–72% compared with that of pure β-CDP. Among them, that of β-CDP/3-hydroxy-2-naphthoic acid ER fluid was the highest. It was also found that the ER effect of supramolecular complexes can be controlled by changing different guests. When the substituted group is at phenyl ring, ER behavior can be slightly adjusted by the different substituted groups, their number as well as their position at phenyl ring. This can be proved by the measurement of dielectric properties.展开更多
Two coordination polymers,namely[Mn(μ-Hcpia)(bipy)(H_(2)O)_(2)]_(n)(1)and[Cd_(3)(μ3-Hcpia)_(2)(μ-Hbiim)_(2)(μ-H_(2)biim)(H_(2)O)_(2)]n(2),have been constructed hydrothermally using H_(2)cbia(H_(2)cbia=5-(4΄-cyano-...Two coordination polymers,namely[Mn(μ-Hcpia)(bipy)(H_(2)O)_(2)]_(n)(1)and[Cd_(3)(μ3-Hcpia)_(2)(μ-Hbiim)_(2)(μ-H_(2)biim)(H_(2)O)_(2)]n(2),have been constructed hydrothermally using H_(2)cbia(H_(2)cbia=5-(4΄-cyano-benzoxy)isophthalic acid),bipy(bipy=4,4΄-bipyridine),H_(2)biim(H_(2)biim=2,2΄-biimidazole),and manganese or cadmium chlorides at 160℃.Interestingly,the H3cpia(H3cpia=5-(4΄-carboxylphenoxy)isophthalic acid)ligand was generated by in situ hydrolysis of cyano group in H_(2)cbia.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses(TGA),and single-crystal X-ray diffraction analyses.Both compounds crystallize in the triclinic system,space group P1.Compound 1 discloses a 1D linear chain of the 2C1 topological type.Adjacent chains are assembled into a 2D supramolecular sheet through O–H∙∙∙O/N hydrogen bonds.Compound 2 features a 3D framework with a 3,4,4T25 topology.The luminescent and catalytic properties of two compounds were investigated.Compound 1 exhibits a superior catalytic activity in the cyanosilylation at room temperature.展开更多
文摘In-situ microscopic FTIR spectroelectrochemical technique(MFTIRs) was applied to studying the electrochemical oxidation of ascorbic acid(AA) in poly(ethylene glycol)(PEG) paste at a 100 μm diameter Pt disk electrode. Using this technique, the catalytic ability of cobalt hexacyanoferrate(CoHCF) microcrystalline toward AA oxidation was also studied. It was found that the dispersed CoHCF powder in the PEG paste can generate well shaped thin layer cyclic voltammetric waves with the peak height proportional to the scan rate, corresponding to the Fe centered redox reactions. This oxidation step catalyzed the AA oxidation. Also, this pasted CoHCF powder generated well resolved in situ MFTIRs spectra, by which a chemical interaction between CC bond of AA ring and CoHCF lattice was revealed. A corresponding surface docking mechanism for the catalytic reaction has been proposed.
基金This work was supported by the National Natural Science Foundation of China
文摘Crosslinking is one of the effective routes for improving the orientation stability of poled polymer films. The derivative of polyvinyl alcohol containing 4-nitro-4'-alkoxystilbene and photo-crosslinkable cinnamyl groups as side chains has been synthesized. The in-situ simultaneous photo-crosslinking poling of synthesized polymer films has teen performed, The second order nonlinear optical coefficient d(33) of poled film is 11 pm/V. The SHG measurements show that the break-over temperature of SHG signal is raised obviously after irradiation, its orientation stability is doubled as compared with that of non-crosslinking samples.
文摘Hybrid proton conducting membranes of poly（vinyl alcohol） （PVA） and phosphomolybdic acid （PMA） were prepared by solution casting method. The effect of PMA doping and PVA crosslinking density on the membrane properties and proton conductivity were investigated. The crosslinking reaction between the hydroxyl group of PVA and the aldehyde group of glutaraldehyde （GA） was characterized by IR spectroscopy. Proton conductivity of the membranes increases with an increase in concentration of the doped PMA and also with an increase in crosslinking density of the membranes. Proton conductivity results indicate that a significant amount of PMA was maintained in the membranes even after several hours of immersion in water. A maximum conductivity of 0.0101 S cm^-1 was obtained for the membrane with 33.3 wt% PMA and crosslinking density of 5.825 mol%. X-ray diffraction studies were carried out to investigate the influence of PMA doping and crosslinking density on the nature of the membranes. These properties make them very good candidates for polymer electrolyte membranes for direct methanol fuel cell application.
基金This work was supported by the National Namral Science Foundation of China(Grant No.59832090)the National Natural Science Foundation of China for Distinguished Young Scholar(Grant No.50025207)the'863'Foundation(Grant No.2001AA327130).
文摘According to the chemical design, electrorheological properties of supramolecular complex from β-cyclodextrin polymer (β -CDP) were discussed. Six supramolecular complexes of β-cyclodextrin polymer with substituted salicylic acid and 3-hydroxy-2-naphthoic acid were synthesized by the solid-phase self-assembly method, and their component and structure were characterized by NMR, FT-IR, UV-vis and the fluorescence analysis. Then the electrorheological properties of their suspensions in silicone oil were investigated under DC electric fields. It was found that the yield stresses of these supramolecular complex ER fluids were 7.3–9.8 kPa at 4 kV/mm in DC electric field, which were enhanced by 34%–72% compared with that of pure β-CDP. Among them, that of β-CDP/3-hydroxy-2-naphthoic acid ER fluid was the highest. It was also found that the ER effect of supramolecular complexes can be controlled by changing different guests. When the substituted group is at phenyl ring, ER behavior can be slightly adjusted by the different substituted groups, their number as well as their position at phenyl ring. This can be proved by the measurement of dielectric properties.
基金the Science and Technology Plan of Qinghai Province(2020-ZJ-705)。
文摘Two coordination polymers,namely[Mn(μ-Hcpia)(bipy)(H_(2)O)_(2)]_(n)(1)and[Cd_(3)(μ3-Hcpia)_(2)(μ-Hbiim)_(2)(μ-H_(2)biim)(H_(2)O)_(2)]n(2),have been constructed hydrothermally using H_(2)cbia(H_(2)cbia=5-(4΄-cyano-benzoxy)isophthalic acid),bipy(bipy=4,4΄-bipyridine),H_(2)biim(H_(2)biim=2,2΄-biimidazole),and manganese or cadmium chlorides at 160℃.Interestingly,the H3cpia(H3cpia=5-(4΄-carboxylphenoxy)isophthalic acid)ligand was generated by in situ hydrolysis of cyano group in H_(2)cbia.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses(TGA),and single-crystal X-ray diffraction analyses.Both compounds crystallize in the triclinic system,space group P1.Compound 1 discloses a 1D linear chain of the 2C1 topological type.Adjacent chains are assembled into a 2D supramolecular sheet through O–H∙∙∙O/N hydrogen bonds.Compound 2 features a 3D framework with a 3,4,4T25 topology.The luminescent and catalytic properties of two compounds were investigated.Compound 1 exhibits a superior catalytic activity in the cyanosilylation at room temperature.
