排序方式: 共有45条查询结果,搜索用时 31 毫秒
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Aline Bruna da Silva Juliano Marini Genaro Gelves Uttandaraman Sundararaj Rinaldo Gregório Jr. Rosario E.S. Bretas 《European Polymer Journal》2013
The objective of this work was to prepare novel conductive blends of poly(vinylidene fluoride) (PVDF) with polypyrrole (PPy) and to compare their performance with PVDF/multiwall carbon nanotube (MWCNT) composites and novel PVDF/PPy/MWCNT hybrid systems. All the compositions were prepared by melt mixing using a miniature mixer. The mixtures were characterized by Fourier transformed infrared (FTIR), wide angle X-ray diffraction (WAXD), thermogravimetric analyses (TGA), scanning and transmission electron microscopy (SEM and TEM, respectively) and volume electrical resistivity. For the binary PVDF/PPy and PVDF/MWCNT systems, percolation thresholds of 10 and 0.3 wt%, respectively, were found. In the hybrid systems, however, the percolation threshold for each filler was lower than in the binary systems, but the electrical conductivities were always much higher at all concentrations than the conductivities of the binary systems. Therefore, the addition of both fillers had a synergistic effect on the hybrid system conductivity, which was attributed to its morphology: the PPy increased the homogeneity of the MWCNT distribution and decreased the available free volume for the MWCNT; as a result the MWCNT rolled around the PPy particles bridging them through the PVDF matrix, increasing the quantum tunneling effect and thus, the electrical conductivity of the system. 相似文献
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We demonstrate that core–shell multi-component nanocomposites can be grown in situ at room temperature by a novel one-step approach without adding any reductant and stabilizer. We have presented a one-step method for the synthesis of multi-component nanocomposites in water solution, the multi-component nanocomposites could be produced directly and quickly in an in situ wet-chemical reaction. Here, Au–polypyrrole (PPy)/Prussian blue (PB) nanocomposites have been synthesized successfully under the same circumstance. With the addition of pyrrole monomers into mixture solutions, the autopolymerization of pyrrole into PPy and AuCl4− was reduced to elemental Au instantaneously as well as simultaneously. At the same time, PB produced along with elemental Au serving as a catalyst. Furthermore, we investigated the performance of Au–PPy/PB nanocomposites as amperometric sensor toward the reduction of H2O2, which displayed high sensitivity, fast response and good stability. The peak current of H2O2 increased linearly with the concentration of H2O2 in the range from 2.5 × 10−9 to 1.2 × 10−6 M, and the low detection limit of 8.3 × 10−10 M (S/N = 3) was obtained. Therefore, this work provides a new pathway to design and fabricate novel multi-component nanocomposites, which have unique characteristics and hold great applications in the fields of sensors, electrocatalysis and others. 相似文献
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Preparation of novel sulfur/polypyrrole (S/PPy) composite consisting well-dispersed sulfur particles anchored on interconnected PPy nanowire network was demonstrated. In such hybrid structure, the as-prepared PPy clearly displays a three-dimensionally cross-linked and hierarchical porous structure, which was utilized in the composite cathode as a conductive network trapping soluble polysulfide intermediates and enhancing the overall electrochemical performance of the system. Benefiting from this unique structure, the S/PPy composite demonstrated excellent cycling stability, resulting in a discharge capacity of 931 mAh g−1 at the second cycle and retained about 54% of this value over 100 cycles at 0.1 C. Furthermore, the S/PPy composite cathode exhibits a good rate capability with a discharge capacity of 584 mAh g−1 at 1 C. 相似文献
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Electrically conducting polypyrrole (PPy) film doped with silicomolybdate (SiMo12
or SiMo12) was synthesized by electrochemical polymerization. The synthesized film is capable of fast charge propagation during redox
reactions in strong acid medium 0.2 M H2SO4 solution. Electrochemical quartz crystal microbalance was used to study the mechanism and amount of SiMo12 doped in the PPy matrix. The modified electrode surface was characterized by using atomic force microscope technique, and
it was found that the minimum and maximum globule size were estimated to be in the range of 50–200 nm. The thickness of film
was measured to be approximately 30 ± 10 nm. The modified electrode shows electrocatalytic activity towards reduction of Cr(VI)
and periodate. The rate constant and optimal film thickness were determined for electrocatalytic reduction of Cr(VI) by using
rotating disc electrode experiment. Analytical characterization of the SiMo12 doped PPy film modified electrode was demonstrated by flow injection analysis (FIA) technique and shows good stability for
16 continuous injections for Cr(VI) reduction with RSD of 1.6%. 相似文献
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纳米尺度TiO2/聚吡咯多孔膜电极光电化学研究 总被引:28,自引:4,他引:28
用光电流作用谱,光电流-电势图和UV-Vis光说研究了TiO2/聚吡咯多孔膜电极在不含氧化还原对和含不同氧化还原体系电解质溶液中的光电转换过程。TiO2/聚吡咯多孔膜电极双层n型半导体结构,内层TiO2多孔膜的禁带宽度为3.26eV,外层聚吡咯膜的禁带宽度为2.2eV。 相似文献
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《Electroanalysis》2006,18(15):1471-1478
In this paper, we present an electrochemical impedance‐based DNA biosensor by using a composite material of polypyrrole (PPy) and multiwalled carbon nanotubes (MWNTs) to modify glassy carbon electrode (GCE). The polymer film was electropolymerized onto GCE by cyclic voltammetry (CV) in the presence of carboxylic groups ended MWNTs (MWNTs‐COOH). Such electrode modification method is new for DNA hybridization sensor. Amino group ended single‐stranded DNA (NH2‐ssDNA) probe was linked onto the PPy/MWNTs‐COOH/GCE by using EDAC, a widely used water‐soluble carbodiimide for crosslinking amine and carboxylic acid group. The hybridization reaction of this ssDNA/PPy/MWNTs‐COOH/GCE resulted in a decreased impedance, which was attributed to the lower electronic transfer resistance of double‐stranded DNA than single‐stranded DNA. As the result of the PPy/MWNTs modification, the electrode obtained a good electronic transfer property and a large specific surface area. Consequently, the sensitivity and selectivity of this sensor for biosensing DNA hybridization were improved. Complementary DNA sequence as low as 5.0×10?12 mol L?1 can be detected without using hybridization marker or intercalator. Additionally, it was found that the electropolymerization scan rate was an important factor for DNA biosensor fabrication. It has been optimized at 20 mV s?1. 相似文献
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Marcel Tintelott Tom Kremers Anabel Mernitz Sven Ingebrandt Vivek Pachauri Xuan Thang Vu Uwe Schnakenberg 《Electroanalysis》2023,35(4):e202200332
A simple equivalent electrical circuit is used to obtain the physical parameters of electrical circuit elements from measured electrochemical impedance spectra. This model consists of four circuit elements with a clear physical meaning for each of the elements. Compared to complex models with multiple constant phase elements or Warburg impedances, our model is suitable for extracting physical values for important electrode parameters with low errors. The feasibility of the model was shown by investigating pure metal or polymer-coated electrodes. Here, gold electrodes were coated either with Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT : PSS), Polypyrrole:poly(styrenesulfonate) (PPy : PSS), or (PEDOT/PPy) : PSS by means of electropolymerization. The model could demonstrate the ionic-electronic differences such as the ion accessibility of the differently coated electrodes. To prove the correctness of the model, the obtained results were compared to the literature. 相似文献