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1.
Catherine Cordier-Robert Thierry Grosdidier Gang Ji Jacques Foct 《Hyperfine Interactions》2006,168(1-3):951-957
Microstructured (atomized) and nanostructured (milled) Fe60Al40 powders together with their corresponding coatings synthesized by High Velocity Oxy-fuel (HVOF) or Atmospheric Plasma Spray (APS) thermal spraying techniques have been characterized by Mössbauer Spectroscopy (MS) and X-ray Diffraction (XRD). The evolution of the microstructure and the atomic ordering degree in the powders and coatings are discussed at the light of the various processing conditions. The operational correlation between the parameters of the duplex morphology of coatings and the processing parameters is discussed. 相似文献
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Polyphenylsilsesquioxane (PPSQ) was incorporated into an epoxy resin to prepare organic–inorganic composites, and two strategies were adopted to afford composites with different morphologies. Phase separation induced by polymerization occurred in the physical blending system. However, nanostructured composites were obtained when a catalytic amount of aluminum triacetylacetonate was added to mediate the reaction between PPSQ and diglycidyl ether of bisphenol A (DGEBA). The intercomponent reaction significantly suppressed the phase separation on the micrometer scale. Organic–inorganic composites with different morphologies displayed quite different thermomechanical properties. Both differential scanning calorimetry and dynamic mechanical analysis showed that the nanostructured composites possessed higher glass‐transition temperatures than the phase‐separated composites with the same loading of PPSQ, although the intercomponent reaction between PPSQ and DGEBA reduced the crosslinking density of the epoxy matrix. This result was ascribed to the presence of nanosized PPSQ domains in the nanostructured composites, which acted as physical crosslinking sites and thus reinforced the epoxy networks. The nanoreinforcement of the PPSQ domains afforded the enhanced dynamic storage modulus for the nanostructured composites in comparison with the phase‐separated composites with a PPSQ concentration less than 15 wt %. In terms of thermogravimetric analysis, the organic–inorganic composites displayed improved thermal stability and flame retardancy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1093–1105, 2006 相似文献
4.
Ken‐ichi Shinohara Tasuku Suzuki Takeshi Kitami Shingo Yamaguchi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(2):801-809
We fabricated a micrometer‐long supramolecular chain in which π‐conjugated polyrotaxane was coupled. A new experimental setup was designed and constructed, and the simultaneous direct imaging of the structure and fluorescent function was achieved. Furthermore, we identified the formation of a polymer intertwined network and observed novel fluorescence due to a long‐range interaction via this intertwined network over a distance of 5 μm or more without quenching over 15 min in the near field. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 801–809, 2006 相似文献
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Nanostructure Pt Electrode Obtained via Self-assembly of Nanoparticles on Conductive Oxide-coated Glass Substrate 总被引:1,自引:0,他引:1
Self-assembly of platinum nanoparticles were applied to fabrication of counter electrode for dye-sensitized solar cells on conductive oxide-coated glass substrate. The present Pt electrode exhibits high exchange current density of 220 mA/cm^2, which is comparable to those prepared by electrodeposition, magnetron sputtering or thermal decomposition of platinum chloride. After analysis by transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), it was found that the catalyst was structurally characterized as nanosized platinum metal clusters and was continuously arranged on electrode surface. The present nanostructure electrode had high electrocatalytic activity for the reduction of iodine in organic solution. 相似文献
7.
TiO2与ZnO复合纳米结构电极的光电化学研究 总被引:2,自引:0,他引:2
利用尿素加压共沉淀法以Ti(SO4)2与Zn(NO3)2为原料制备了TiO2-ZnO复合纳米粒子, 其纳米结构电极的光电化学研究结果表明, 反应物摩尔比为3∶1, 于530 ℃煅烧制备的复合纳米结构电极的光电转换效率最高. 对吸附染料RuL2(SCN)2∶2TBA的纳米结构TiO2和各种复合纳米粒子的纳米结构电极进行光电研究的结果表明, 染料对各纳米结构电极都起到了敏化作用, 其中也是由反应物摩尔比为3∶1, 于530 ℃煅烧制备的纳米结构电极的光电转换效率最高. 对聚3-甲基噻吩修饰的纳米结构TiO2和摩尔比为3∶1, 于530 ℃煅烧的复合纳米粒子构成的纳米结构电极进行光电性能研究, 结果表明, 聚3-甲基噻吩与半导体纳米粒子之间存在p-n结, 在一定条件下p-n结的存在有利于光生电子/空穴的分离, 从而提高了光电转化效率. 相似文献
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Shouhong Xu Yuan Song Shizuko Sato Isamu Miyata Junpei Yamanaka Masakatsu Yonese 《Colloid and polymer science》2005,283(4):383-392
Two-dimensional structures and characteristics of the complexes between sodium hyaluronate (NaHA) and bovine serum albumin (BSA) were studied by using a quartz crystal microbalance method and an atomic force microscope (AFM). NaHA did not adsorb on poly(-methyl-l-glutamate) (PMLG) film. On the other hand, the complexes adsorbed on it and the adsorption behaviors were found to be Langmuir types. With increasing weight ratio of BSA to NaHA, W
BSA, the adsorption constants K decreased and the saturated adsorption masses increased. The adsorbed complexes were spherical particles and at saturated adsorption states they covered compactly on the PMLG film. The mean diameters d
AFM estimated from the topographic images decreased from 70 to 54 nm with increasing W
BSA. The adhesion force F
ad and the frictional force F
f between the complex layers and the AFM tip were obtained by using the contact mode of the AFM. With increasing W
BSA, the values of F
ad decreased and the values of F
f increased. Compared with the frictional coefficient of the NaHA adsorption layer on the BSA monolayer, the values for the NaHA–BSA complex layer were found to be much higher. 相似文献
10.
M.C. Silva G. Trolliard O. Masson R. Guinebretiere A. Dauger A. Lecomte B. Frit 《Journal of Sol-Gel Science and Technology》1997,8(1-3):419-424
Three different precursor materials giving rise to contrasted nanostructures, xerogels, aerogels and precipitates, are prepared by a sol gel route in the Zrn -propoxide—acetylacetone—water—n-propanol system. Clear homogeneous gels are made by using a proper amount of acetylacetone and water. The gels are dried either by conventional processing (xerogels) or by supercritical evacuation of alcoholic solvent (aerogels). The complexation ratio (R = [acetylacetone]/[Zr(OR)4]) is the main parameter controlling the size of ZrO2 primary particles. WhenR = 0 , precipitates are obtained.Xerogels, aerogels and precipitates are characterized and their textures are compared through small angle X-ray scattering measurements. The fractal structure of gels is destroyed by conventional drying and is preserved in aerogels. On the other hand precipitates are described as homogeneous agglomerates of very small primary units.The first crystallization steps are studied by transmission electron microscopy and X-ray diffraction experiments. The contribution of crystallite size and microstrain effects are investigated by Rietveld whole pattern fitting. The crystallization of precipitate powders starts at the agglomerate scale with large crystal like distorted lattices. 相似文献