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排序方式: 共有1002条查询结果,搜索用时 15 毫秒
141.
Valter Bavastrello Tercio Bezerra Correia TerencioLuca Belmonte Pierluigi CossariClaudio Nicolini 《Thin solid films》2012,520(18):5877-5883
Poly(o-methoxyaniline) and poly(o-methylaniline) were synthesized by oxidative polymerization in the presence of multi-walled carbon nanotubes (MWNT) for the fabrication of chloroform processable nanocomposites obtained by embedding MWNT in the polymer matrix without the formation of covalent bonds. The study of pressure-area isotherms highlighted different substituents along the aromatic rings affected the packing grade of macromolecules when spreading on different subphases in relation to the associated sterical hindrance. The presence of MWNT inside the polymer matrix showed to favor a more stretched conformation of macromolecules with a subsequent increment of area/molecule values with respect to the corresponding pure conducting polymers. Furthermore, the sterical hindrance affected the nanocomposite electrochemical properties and conducting polymers containing less hindering substituents along the aromatic rings turned out to be faster electrochemical systems. Less hindering substituents were also able to enhance the conducting properties of nanocomposite materials in association with MWNT. 相似文献
142.
Qiang Li Jianhua LiuJianhua Zou Anindarupa ChunderYiqing Chen Lei Zhai 《Journal of power sources》2011,196(1):565-572
Multi-walled carbon nanotube (MWCNT)/polyaniline (PANI)/MnO2 (MPM) ternary coaxial structures are fabricated as supercapacitor electrodes via a simple wet chemical method. The electrostatic interaction between negative poly(4-styrenesulfonic acid) (PSS) molecules and positive Mn2+ ions causes the generation of MnO2 nanostructures on MWCNT surfaces while the introduction of PANI layers with appropriate thickness on MWCNT surfaces facilitates the formation of MWCNT/PANI/MnO2 ternary coaxial structures. The thickness of PANI coatings is controlled by tuning the aniline/MWCNT ratio. The effect of PANI thickness on the subsequent MnO2 nanoflakes attachment onto MWCNTs, and the MPM structures is investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FESEM). The results suggest that appropriate thickness of PANI layers is important for building MPM ternary coaxial structures without the agglomeration of MnO2 nanoflakes. The MPM ternary coaxial structures provide large interaction area between the MnO2 nanoflakes and electrolyte, and improve the electrochemical utilization of the hydrous MnO2, and decrease the contact resistance between MnO2 and PANI layer coated MWCNTs, leading to intriguing electrochemical properties for the applications in supercapacitors such as a specific capacitance of 330 Fg−1 and good cycle stability. 相似文献
143.
Xiaoju WangPia Sjöberg-Eerola Kirsi ImmonenJohan Bobacka Mikael Bergelin 《Journal of power sources》2011,196(11):4957-4964
The immobilization of Trametes hirsuta laccase (ThL) in the poly(3,4-ethylenedioxythiophene) (PEDOT) and polyaniline (PANI) matrices was carried out in order to study the catalytic effect of ThL in different biocathode structures in a biofuel cell application. By using 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonate) (ABTS) as a mediator compound, the immobilized ThL in both polymer matrices, exhibited catalytic activity for the reduction of oxygen into water. The amount of ThL was adjustable in the PEDOT matrix by controlling the working parameters, such as the charge density used in the electropolymerization of EDOT monomer and the ThL concentration used in the electropolymerization electrolyte. In the PEDOT biocathode structure, the utilization of porous material as the PEDOT supporting template was studied in order to improve the current density generated per unit area/volume. Reticulated vitreous carbon foam (RVC foam) was chosen as the PEDOT supporting template material and the biocathodes were manufactured by in situ entrapment of ThL into PEDOT films polymerized on the RVC foam. These biocathodes possessed a high cathodic open circuit potential and produced a large current density, reaching 1 mA cm−3 at 0.45 V when 19.5 μg ml−1 of ThL was used in the electrolyte. The performance of these biocathodes was extremely sensitive to variations in pH and the optimal working pH was around 4.2. The biocathode reserved 80%, 50%, and 30% of the catalytic activity after storage in a +4 °C buffer solution for 1 day, 1 week, and 1 month, respectively. The PANI matrix was prepared in a form of printable ink where ThL was in situ entrapped in the PANI matrix during the laccase activated polymerization of aniline using a chemical batch reactor method. Different amounts of the ThL-containing printable PANI ink were then applied on carbon paper and the performance of the ink was subsequently electrochemically characterized. In this way, not only two different polymer matrices, but also two different matrix manufacturing procedures could be compared. 相似文献
144.
Self-assembled polyaniline nanorods were synthesized by the oxidation of aniline with ammonium peroxydisulfate in an aqueous solution in the presence of 3,5-dinitrosalicylic acid, using the template-free falling-pH method. The effects of the mole ratio of 3,5-dinitrosalicylic acid to aniline, i.e., of starting pH, monomer concentration, and reaction time on the yield of polymerization, molecular-weight distribution, molecular structure, morphology, and conductivity of the prepared polyanilines have been studied by gel-permeation chromatography, elemental analysis, FTIR and Raman spectroscopies, scanning and transmission electron microscopies, and conductivity measurements. The weight-average molecular weights and polydispersity index were in the range 36,400-54,900 and 3.7-7.6, respectively. Synthesized polyaniline nanorods have a diameter of 25-280 nm and a length of 0.2-1.3 μm, and conductivities in the range (1.2-4.6) × 10−2 S cm−1. The formation mechanism of self-assembled polyaniline nanorods has been discussed. 相似文献
145.
Preparation of graphene nanosheet/carbon nanotube/polyaniline composite as electrode material for supercapacitors 总被引:1,自引:0,他引:1
Graphene nanosheet/carbon nanotube/polyaniline (GNS/CNT/PANI) composite is synthesized via in situ polymerization. GNS/CNT/PANI composite exhibits the specific capacitance of 1035 F g−1 (1 mV s−1) in 6 M of KOH, which is a little lower than GNS/PANI composite (1046 F g−1), but much higher than pure PANI (115 F g−1) and CNT/PANI composite (780 F g−1). Though a small amount of CNTs (1 wt.%) is added into GNS, the cycle stability of GNS/CNT/PANI composite is greatly improved due to the maintenance of highly conductive path as well as mechanical strength of the electrode during doping/dedoping processes. After 1000 cycles, the capacitance decreases only 6% of initial capacitance compared to 52% and 67% for GNS/PANI and CNT/PANI composites. 相似文献
146.
Supercapacitive properties of hybrid films of manganese dioxide and polyaniline based on active carbon in organic electrolyte 总被引:1,自引:0,他引:1
Wu-yuan Zou Ben-lin He Ming-liang Sun Yan-sheng Yin 《Journal of power sources》2010,195(21):7489-8287
This is the first report about supercapacitive performance of hybrid film of manganese dioxide (MnO2) and polyaniline (PANI) in an organic electrolyte (1.0 M LiClO4 in acetonitrile). In this work, a high surface area and conductivity of active carbon (AC) electrode is used as a substrate for PANI/MnO2 film electro-codeposition. The redox properties of the coated PANI/MnO2 thin film exhibit ideal capacitive behaviour in 1 M LiClO4/AN. The specific capacitance (SC) of PANI/MnO2 hybrid film is as high as 1292 F g−1 and maintains about 82% of the initial capacitance after 1500 cycles at a current density of 4.0 mA cm−2, and the coulombic efficiency (η) is higher than 95%. An asymmetric capacitor has been developed with the PANI/MnO2/AC positive and pure AC negative electrodes, which is able to deliver a specific energy as high as 61 Wh kg−1 at a specific power of 172 W kg−1 in the range of 0-2.0 V. These results indicate that the organic electrolyte is a promising candidate for PANI/MnO2 material application in supercapacitors. 相似文献
147.
Nicholas Martyak Page McAndrew John McCaskie Julien Dijon 《Science and Technology of Advanced Materials》2013,14(4):345-352
Cyclic polarization measurements made on steel, iron oxalate-coated steel and polyaniline in a high pH solution and in the absence of chloride ions showed no tendency of the surface towards pitting corrosion. In all cases, the pitting potential was similar to the protection potential. Chlorides in the caustic solution caused significant pitting in the bare steel and slight pitting in the oxalate coated steel. The polyaniline coated-steel showed no pitting in the chloride-containing alkaline solution. Scratches through the polyaniline coating did not initiate pitting in the polyaniline coated steel surface when tested in the chloride-containing solutions. 相似文献
148.
Haoyu Zhang 《Polymer》2008,49(25):5504-5512
In this study, multilayer films composed of alternate polyaniline (PANI) and azo-polyelectrolyte (PNACN, PPAPE, PNANT or PNATZ) layers were fabricated through the electrostatic layer-by-layer self-assembly scheme. In the electrostatic adsorption process, PANI was used as the polycation and the azo polyelectrolytes were used as the polyanion. The multilayer growth was monitored by UV-vis spectroscopy and optical ellipsometry. The photoresponsive and electrochromic properties of the multilayer films were studied by UV-vis spectroscopy and electrochemical measurement. Results show that the multilayer films exhibit linear increases in both the absorbance and film thickness with the increase of the deposition cycles. The thickness contributed by each individual layer depends on the pH of the PANI and azo-polyelectrolyte dipping solutions. The multilayer films can show photoinduced dichroic properties contributed by the azo-polyelectrolyte layers, but the ability to form surface-relief-grating (SRG) upon Ar+ laser irradiation is relatively weak. The multilayer films possess the characteristic absorption bands related to the azo chromophores and PANI. As the location of the PANI bands depends on its oxidation states, the multilayer films can show sensitive electrochromic variation. For instance, the PANI/PNACN multilayer films can undergo a transition from transparent yellow-green through deep green to opaque black when the potential changes from −0.1 to 0.8 V. It is demonstrated that using the azo polyelectrolytes with different hues, enriched spectrum of the colors can be obtained by the electrochemical transitions. The multilayer films containing both photoresponsive and electroactive components can be expected for applications in optics, photonic devices and others. 相似文献
149.
Javed Alam Ufana Riaz S. M. Ashraf Sharif Ahmad 《Journal of Coatings Technology and Research》2008,5(1):123-128
The application of nanotechnology in the corrosion protection of metals has recently gained momentum. A polymer nanocomposite
coating can effectively combine the benefits of organic polymers, such as elasticity and water resistance, to that of advanced
inorganic materials, such as hardness and permeability. Environmental impact can also be improved by utilizing nanostructure
particulates in coatings and eliminating the requirement of toxic solvents. Nanocomposites have also proven to be an effective
alternative to phosphate-chromate pretreatment of metallic substrate, which is hazardous due to the presence of toxic hexavalent
chromium. This article reports some of the preliminary investigations on the corrosion-resistance performance of soya oil
alkyd, containing polyaniline/ferrite nanocomposite. The corrosion-protective performance was evaluated in terms of physico-mechanical
properties, corrosion rate, and SEM studies. The polyaniline/ferrite nanocomposite coatings were found to show a far superior
corrosion-resistance performance compared to that of a pure PANI/alkyd system. 相似文献
150.
Robert Gloukhovski Yoram Oren Charles Linder Viatcheslav Freger 《Journal of Applied Electrochemistry》2008,38(6):759-766
A novel approach to preparation of composite asymmetric nanofiltration membranes is reported based on a thin selective layer
deposited by electropolymerization (EP) on top of an asymmetrically porous and electronically conductive porous support. Support
films with ultrafiltration characteristics were cast from a concentrated dispersion of carbon black particles, a few tens
of nanometers large, in a solution of polysulfone followed by precipitation in a non-solvent bath (phase inversion). Composite
membranes with poly(phenylene oxide) and polyaniline thin top layers were prepared by EP deposition from solutions of phenol
and aniline, respectively, of which polyaniline film demonstrated a dense uniform structure and water flux and rejection to
sucrose and magnesium sulfate in the nanofiltration range. 相似文献