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51.
This study describes the preparation of polypyrrole (PPy)/multiwalled carbon nanotube (MWNT) composites by in situ chemical oxidative polymerization. Various ratios of MWNTs, which served as hard templates, were first dispersed in aqueous solutions with the surfactant cetyltrimethylammonium bromide to form micelle/MWNT templates and overcome the difficulty of MWNTs dispersing into insoluble solutions of pyrrole monomer, and PPy was then synthesized via in situ chemical oxidative polymerization on the surface of the templates. Raman spectroscopy, Fourier transform infrared (FTIR), field‐emission scanning electron microscopy (FESEM), and high‐resolution transmission electron microscopy (HRTEM) were used to characterize the structure and morphology of the fabricated composites. Structural analysis using FESEM and HRTEM showed that the PPy/MWNT composites were core (MWNT)–shell (PPy) tubular structures. Raman and FTIR spectra of the composites were almost identical to those of PPy, supporting the idea that MWNTs served as the core in the formation of a coaxial nanostructure for the composites. The conductivities of these PPy/MWNT composites were about 150% higher than those of PPy without MWNTs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1413–1418, 2006 相似文献
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通过实验分析确立了把光纤电阻作为衡量气密性碳涂覆光纤通过2%应变筛选的过渡标准。要拉制2%应变筛选的碳涂覆光纤,其电阻值应小于30kΩ/cm。 相似文献
54.
Both homogeneous and asymmetric polyethersulfone (PES) membranes were prepared by solvent casting. The sorption and permeation behavior of CO2, O2, and N2 using these two kinds of cast PES membranes and commercially available homogeneous PES film was investigated to extract the pressure dependence of gas permeability and the permselectivity for CO2 relative to N2, and to confirm the validity of the working assumption that a skin layer in an asymmetric membrane can be essentially replaced by a thick homogeneous dense membrane. The pressure dependence of the mean permeability coefficient to CO2 in homogeneous membranes obeys the dual-mode mobility model. The ideal separation factor for CO2 relative to N2 at an upstream pressure of 0.5 MPa attains ca. 40, while the permeability to CO2 is about 2.7 Barrer at the same upstream pressure. The same separation factor in asymmetric membranes amounts to 35. The diffusion behavior for the skin layer in an asymmetric membrane with a thin skin layer can be simulated approximately by that in a homogeneous dense membrane. © 1993 John Wiley & Sons, Inc. 相似文献
55.
根据出现在质谱中的各种大小的碳原子簇的相对丰度,分析了由激光产生的碳原子簇离子的统计分布,研究了这些统计分布与碳原子簇结构的关联。研究结果表明:相同构型的原子簇的相对丰度可以由同一条对数正态分布曲线来描述,由此能够获得碳原子簇构型的变化情况。质谱中分布曲线的数目对应于具有不同构型或不同结构稳定性的原子簇的数目。如果某些簇离子的谱峰明显地高出分布曲线,它们的结构应特别稳定,其成簇原子数就是所谓的“奇幻数”(magicnumber),例如在石墨质谱中的C_(60)就属于这种情况。原子簇的统计分布还与它们的生成过程有关,由此可能揭示出原子簇的产生机理。 相似文献
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Carbon Nanotubes in Analytical Sciences 总被引:1,自引:0,他引:1
Arben Merkoçi 《Mikrochimica acta》2006,152(3-4):157-174
59.
Investigation of the electrocatalytic behavior of single-wall carbon nanotube films on an Au electrode 总被引:1,自引:0,他引:1
The voltammetric behavior of uric acid (UA) was studied with an Au electrode modified with single-wall carbon nanotubes (SWNTs). In 0.1 M HAc-NaAc buffer solution (pH 5.0), the SWNT-modified electrode shows high electrocatalytic activity toward UA oxidation. The electro-oxidation of UA is an irreversible diffusion-controlled process with a diffusion coefficient (D) of 8.85×10−6 cm2 s−1. The peak current increases linearly with the concentration of UA in the range of 4.0×10−6-7.0×10−4 M. The detection limit is 1.0×10−6 M. The SWNT was characterized with scanning electron microscopy (SEM). Furthermore, the SWNT-modified electrode has favorable electrocatalytic activity toward dopamine and norepinephrine. This SWNT-modified electrode can also separate the electrochemical responses of uric acid, norepinephrine and ascorbic acid. 相似文献
60.
《Electroanalysis》2005,17(11):997-1002
Binding reactions of toluidine blue (TB) with herring fish DNA in pH 6.0 Britton–Robinson (B–R) buffer solution have been investigated by cyclic voltammetry and linear‐sweep voltammetry at a glassy carbon electrode. TB has a couple of well‐defined redox peaks. The addition of DNA into the TB solution resulted in the decrease of the redox‐peak currents and the shift negatively of the anodic peak potential. The values of the electrochemical parameters such as the electron number of the electrochemical reaction, the electron transfer coefficient and the electrochemical reaction standard rate constant in the absence and presence of DNA, as well as the values of binding constant and binding ratio of DNA with TB were obtained. Almost unchanged values of the electrochemical parameters in the absence and presence of DNA show that nonelectroactive complexes were formed when TB interacted with DNA. DNA concentration can be determined by the decrease of the peak current of TB. The binding mode of TB with DNA was discussed. 相似文献