The electrochemical copolymerization of aniline and N,N,N'-trimethylthionin (azure B) in aqueous solutions has been carried out using the potential sweep method. The optimum conditions for the coelectrodeposition ...The electrochemical copolymerization of aniline and N,N,N'-trimethylthionin (azure B) in aqueous solutions has been carried out using the potential sweep method. The optimum conditions for the coelectrodeposition are that the pH value and the temperature of the electrolytic solution are controlled at 5.57 and 30 degreesC, respectively, and the scan potential range is set between -0.25 and 1.10 V (versus SCE). The copolymerization rate of aniline and azure B is about 3 times larger than that of aniline in the absence of azure B. The copolymerization of aniline and azure B was verified from the results of visible spectra during electrolysis, FTIR spectra and the atomic force microscopy (AFM) images of the polymers. The in situ visible spectrum for the electrolysis of the solution containing aniline and azure B is different from that of the respective aniline and azure B. The FTIR spectrum of the copolymer is not a superposition of that of polyaniline and poly(azure B). The AFM image of the copolymer is different from those of polyaniline and poly(azure B) and is not a mixture of individual polymers. The conductivity of the copolymer synthesized at pH 5.57 is four orders of magnitude higher than that of polyaniline synthesized under the same conditions, but in the absence of azure B. The electrochemical properties of the copolymer are mainly attributed to polyaniline, but the copolymer has a better electrochemical reversibility and a much faster charge transfer than those of polyaniline.展开更多
Nanostructure fabrication from block copolymers in my group normally involves polymer design, synthesis, self-assembly, selective domain crosslinking, and sometimes selective domain removal. Preparation of thin films ...Nanostructure fabrication from block copolymers in my group normally involves polymer design, synthesis, self-assembly, selective domain crosslinking, and sometimes selective domain removal. Preparation of thin films withnanochannels was used to illustrate the strategy we took. In this particular case, a linear triblock copolymer polyisoprenc-block-poly(2-cinnamoylethyl methacrylate)-block-poly(t-butyl acrylate), PI-b-PCEMA-b-PtBA, was used. Films, 25 to50 μm thick, were prepared from casting on glass slides a toluene solution of PI-b-PCEMA-b-PtBA and PtBA homopolymer,hPtBA, where hPtBA is shorter than the PtBA block. At the hPtBA mass faction of 20% relative to the triblock or the totalPtBA (hPtBA and PtBA block) volume fraction of 0.44, hPtBA and PtBA formed a seemingly continuous phase in the matrixof PCEMA and Pl. Such a block segregation pattern was locked in by photocrosslinking the PCEMA domain. Nanochannelswere formed by extracting out hPtBA with solvent. Alternatively. larger channels were obtained from extracting out hPtBAand hydrolyzing the t-butyl groups of the PtBA block. Such membranes were not liquid permeable but had gas permeabilityconstants ～6 orders of magnitude higher than that of low-density polyethylene films.展开更多
通过扫描电子显微镜观察了天然橡胶和高吸水树脂共混体系的微观相态结构 ,研究了两亲性嵌段共聚物PEO b PBA结构本身的吸水能力对天然橡胶和高吸水性树脂共混体系吸水性能及力学性能的影响。结果表明 ,PEO b PBA结构本身的吸水强弱对共...通过扫描电子显微镜观察了天然橡胶和高吸水树脂共混体系的微观相态结构 ,研究了两亲性嵌段共聚物PEO b PBA结构本身的吸水能力对天然橡胶和高吸水性树脂共混体系吸水性能及力学性能的影响。结果表明 ,PEO b PBA结构本身的吸水强弱对共混体系的吸水能力贡献很小 ,但却可以显著提高共混体系的吸水膨胀能力和力学性能 。展开更多
The behavior of poly(ethylene glycol)-b-poly(butylene terephthalate) copol ymer has been investigated. The influences of the immersing time(in phosphate buffer solution of pH=7 4, at (37±1) ℃) on the sw elling r...The behavior of poly(ethylene glycol)-b-poly(butylene terephthalate) copol ymer has been investigated. The influences of the immersing time(in phosphate buffer solution of pH=7 4, at (37±1) ℃) on the sw elling ratio, the mass loss and the surface morphology of the copolymer film were examined. The copolymer is found to be degradable. The m icrospheres of PEG-b-PBT were prepared by a solvent extraction method using PVA as a stabilizer and characteristic of a sm ooth and spherical surface, sized about 1 133 μm. IR and XRD results reveal that Levonorgestrel crystalls are physically entrapped in the microspheres of the copolymer.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 20074027), the State Key Laboratory of Physical Chemistry of the Solid Surface at Xiamen University and the Laboratory of Organic Solids, Institute of Chemistry, Chinese Aca
文摘The electrochemical copolymerization of aniline and N,N,N'-trimethylthionin (azure B) in aqueous solutions has been carried out using the potential sweep method. The optimum conditions for the coelectrodeposition are that the pH value and the temperature of the electrolytic solution are controlled at 5.57 and 30 degreesC, respectively, and the scan potential range is set between -0.25 and 1.10 V (versus SCE). The copolymerization rate of aniline and azure B is about 3 times larger than that of aniline in the absence of azure B. The copolymerization of aniline and azure B was verified from the results of visible spectra during electrolysis, FTIR spectra and the atomic force microscopy (AFM) images of the polymers. The in situ visible spectrum for the electrolysis of the solution containing aniline and azure B is different from that of the respective aniline and azure B. The FTIR spectrum of the copolymer is not a superposition of that of polyaniline and poly(azure B). The AFM image of the copolymer is different from those of polyaniline and poly(azure B) and is not a mixture of individual polymers. The conductivity of the copolymer synthesized at pH 5.57 is four orders of magnitude higher than that of polyaniline synthesized under the same conditions, but in the absence of azure B. The electrochemical properties of the copolymer are mainly attributed to polyaniline, but the copolymer has a better electrochemical reversibility and a much faster charge transfer than those of polyaniline.
文摘Nanostructure fabrication from block copolymers in my group normally involves polymer design, synthesis, self-assembly, selective domain crosslinking, and sometimes selective domain removal. Preparation of thin films withnanochannels was used to illustrate the strategy we took. In this particular case, a linear triblock copolymer polyisoprenc-block-poly(2-cinnamoylethyl methacrylate)-block-poly(t-butyl acrylate), PI-b-PCEMA-b-PtBA, was used. Films, 25 to50 μm thick, were prepared from casting on glass slides a toluene solution of PI-b-PCEMA-b-PtBA and PtBA homopolymer,hPtBA, where hPtBA is shorter than the PtBA block. At the hPtBA mass faction of 20% relative to the triblock or the totalPtBA (hPtBA and PtBA block) volume fraction of 0.44, hPtBA and PtBA formed a seemingly continuous phase in the matrixof PCEMA and Pl. Such a block segregation pattern was locked in by photocrosslinking the PCEMA domain. Nanochannelswere formed by extracting out hPtBA with solvent. Alternatively. larger channels were obtained from extracting out hPtBAand hydrolyzing the t-butyl groups of the PtBA block. Such membranes were not liquid permeable but had gas permeabilityconstants ～6 orders of magnitude higher than that of low-density polyethylene films.
文摘通过扫描电子显微镜观察了天然橡胶和高吸水树脂共混体系的微观相态结构 ,研究了两亲性嵌段共聚物PEO b PBA结构本身的吸水能力对天然橡胶和高吸水性树脂共混体系吸水性能及力学性能的影响。结果表明 ,PEO b PBA结构本身的吸水强弱对共混体系的吸水能力贡献很小 ,但却可以显著提高共混体系的吸水膨胀能力和力学性能 。
文摘The behavior of poly(ethylene glycol)-b-poly(butylene terephthalate) copol ymer has been investigated. The influences of the immersing time(in phosphate buffer solution of pH=7 4, at (37±1) ℃) on the sw elling ratio, the mass loss and the surface morphology of the copolymer film were examined. The copolymer is found to be degradable. The m icrospheres of PEG-b-PBT were prepared by a solvent extraction method using PVA as a stabilizer and characteristic of a sm ooth and spherical surface, sized about 1 133 μm. IR and XRD results reveal that Levonorgestrel crystalls are physically entrapped in the microspheres of the copolymer.
