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1.
This study describes the formation of composites of polyaniline (PANI)-Carbon Nanotube (CNT) using in situ chemical oxidative polymerization of the monomer aniline. The PANI-CNT composites were characterized by FTIR and UV-Visible spectroscopy and XRD method. The surface morphology of the composites was characterized by scanning electron microscopy (SEM). Pseudo-capacitive behavior of deposited PANI over the surface of CNT was investigated by means of cyclic voltammetry. The composite was mixed with activated carbon for making the electrode. The specific capacitance of the prepared electrode was tested by means of a half cell test. The PANI-CNT composite with 0.02 M aniline in initial polymerization solution had the thinnest layer and highest specific capacitance of 597.82 F/g in 1 M H 2SO 4. 相似文献
2.
Nanostructured polyanilines of different morphologies were prepared by chemical polymerization of aniline with ammonium peroxodisulfate in aqueous HCl using various inorganic and organic chlorides as additives with the aim to determine the effect of cations of the added electrolyte on the morphology, spectroscopic characteristics, and conductivity of formed polyanilines. Chlorides of basic metals: NaCl and CaCl 2 did not show any significant effect while AlCl 3 and organic electrolytes were found to influence the morphology of polyanilines. The effect of organic-electrolyte additives, which actually are ionic liquids, is explained by the organization of their molecules to micellar structures that act as soft templates for emerging polyaniline nanoparticles. The effect of AlCl 3 is ascribed to the transformation of its molecules to [AlCl 4] ? anions. 相似文献
3.
We describe the preparation of polyaniline (PANI‐EB) by aniline oxidation with KIO 3 and the purification of the resulting dedoped polymer by an acetone extraction step to eliminate undesired by‐products from polyaniline, which could generate some safety concerns in the application and use of PANI. Excellent homogeneous and electrically conducting composite films can be prepared from chloroform solutions of purified PANI doped with camphorsulfonic acid in presence of cis‐1,4‐polybutadiene as the film‐forming agent. These films have been characterized by FT‐IR and UV‐VIS‐NIR spectroscopy. A method to synthesisze PANI directly doped with dodecylbenzenesulfonic acid (DBSA) is also reported. DBSA‐doped‐PANI was then used to prepare composites with polyphenylacetylene (PPA) by growing homogeneous films from chloroform solution. These films were conductive and were studied by FT‐IR and UV‐VIS‐NIR spectroscopy. In view of the application of these composites as gas sensors or in “electronic noses”, a short discussion is presented about the criteria used in the selection of the chemical nature of the host polymer where doped PANI is included to confer electrical conductivity. The interaction between the molecules to be detected and the polymeric sensing surface is discussed in terms of physisorption, chemisorption and charge‐transfer‐complex formation. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
4.
Bimetallic Co–Cu polyaniline composites were produced by oxidative polymerization of aniline, with ammonium peroxydisulfate and hydrogen peroxide as oxidizing agents. Co(II) and Cu(II) chlorides were introduced into the polymer by the in situ method. It was found that the phase constitution of the composites is affected by their synthesis conditions and content of both metals in them. The electrocatalytic activity of the composites in the electrohydrogenation of p-nitroaniline in an aqueous-alcoholic-alkaline medium of the catholyte was studied and found to exceed that of composites synthesized with the use of H 2O 2 and evaporation of the solvent. 相似文献
5.
Nanosized metal and polyaniline (PANi) composite spheres have been prepared via the polymerization of aniline using PdCl 2 or HAuCl 4 as the oxidant in a microemulsion system. The oxidization of aniline and the reduction of metal ion happened together during the reaction, yielding PANi and elemental metal simultaneously. The results of FTIR spectra suggested that the oxidation degree of PANi was affected by the initial ratio of metal ions to monomer in the microemulsion system. The PANi–metal nanospheres were characterized using X-ray photoelectron spectroscopy and the conductivity of the composite nanospheres was measured by conventional four-probe method. Scanning and transmission electron microscopy were used to show the morphology of the composites. 相似文献
6.
Volta potential differences measured at 298.15 K were used to determine the real primary effect of the medium of calcium ions and the real Gibbs energy of transfer of Ca 2+ from water into a mixed water-acetone (Me 2CO) solvent. The surface potential at the solvent/gas phase interface was found to be $\Delta \chi ^{Me_2 CO} = - 0.337V$ . This value was used to calculate the chemical thermodynamic characteristics of calcium ions. The thermodynamic characteristics of resolvation of the 2-1 electrolyte are compared with those obtained earlier for a 1-1 electrolyte. 相似文献
7.
This paper is devoted to the preparation of polyaniline/lead dioxide composites (PANI/PbO 2) via chemical oxidation of aniline in H 2SO 4 medium using β-PbO 2 as an oxidant. The parameters affecting the polymerization reaction are considered. These parameters are [aniline], amount of β-PbO 2, stirring time, and different acids. The prepared composites were characterized by SEM, FT-IR, XRD, TGA, DTA, and elemental analysis. From XRD and FT-IR spectra, it was concluded that high molecular weight polymer could be obtained with high aniline concentration, high amount of β-PbO 2, increasing polymerization time and polymerization of ANI at lower temperatures. Thermogravimetric study exhibited that the composite prepared using high amount of β-PbO 2 has a higher thermal stability. The application of the composites in the oxidative degradation of Alizarin yellow G and Acid alizarin violet N dyes exhibited good catalytic activity in presence of H 2O 2 as an oxidant. The reactions followed first-order kinetics and the rate constants were determined. 相似文献
8.
Ionic liquid like 1-butyl-3-methyl-imidazolium tetrafluorobrate ([BMIM]BF 4) has been used as solvent and electrolyte for the electropolymerization of aniline at glassy carbon electrode by cyclic voltammetry.
Electrode modified with polyaniline (PAn) has obvious electrochemical activity in ionic liquid and acid solution (pH 0–4),
and has significant electrocatalytic activity for redox reaction of catechol and hydroquione.
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Translated from Journal of East China Normal University ( Natural Science), 2005, 3 (in Chinese) 相似文献
9.
A novel method for homogenous incorporation of Ru (RuO 2, or RuO 3) into high aspect ratio anodic TiO 2 NTs was studied. TiO 2 NTs were prepared by anodization in HF based electrolyte, after which very short high applied potential, referred to as potential shock, was imposed on the TiO 2 NTs in KRuO 4 electrolyte. The high potential shock induced massive flow of RuO 4− to positively-biased TiO2 NTs, resulting in the incorporation of Ru as a form of Ru, RuO 2, and RuO 3 in the TiO 2 NTs. Optimal potential shock, which allowed the most suitable amount and incorporation state of Ru catalysts in TiO 2 NTs, was determined by SEM, TEM, EDS, XPS, and LSV. It was demonstrated that electrochemical potential shock (simply imposed on the anodic TiO 2 for a few seconds in the electrolyte of KRuO 4) resulted in homogenous incorporation of Ru into the whole nanotubes without the need for any complicated steps or facilities. 相似文献
10.
Anodic TiO 2 films with a doping of Ru ions on the surface were coincidently prepared by facile one-step anodization for application of the electrode in electrolysis. We found that the amount of Ru ions on the surface of the oxide could be determined based on the applied potential in KRuO 4 electrolyte, which provided negative RuO 4– ions through dissociation. Overpotentials for the evolution of both O 2 and Cl 2 were greatly reduced when the coincidently-Ru-doped TiO 2 was employed. The Ru-doped electrode prepared at 60 V showed the highest electrocatalytic activity due to the largest amount of Ru incorporation in the oxide. 相似文献
11.
A simple technique of preparing a continuous laminar liquid flow in vacuum (liquid beam) was developed and combined with multiphoton ionization and a time-of-flight mass spectrometer. This technique was applied to the study on resonance photoionization of an aniline (AN)-propanol (PrOH) solution (0.1 – 0.3 M). Binary cluster ions of aniline and propanol, AN +(PrOH) n (n ≤ 1), and protonated propanol cluster ions, H +(PrOH) n (n ≤ 1), were observed as product ions in the gas phase. The relative intensities of AN +PrOH and those of H +(PrOH) 2 were measured as functions of the excitation laser power and the concentration of aniline in the propanol solution. The dependences of the ion intensities on the laser power and the AN concentration are explained in terms of a Coulomb ejection model, where the ions are ejected from the surface by Coulomb repulsion exerted from neighboring ions. It is also concluded that H +(PrOH) n is produced by a proton transfer reaction from an aniline ion to solvent molecules in the solution. 相似文献
12.
The proposed extension to the Stokes and Robinson hydration theory is based on the premise that H 2O molecules of electrolyte solutions reside in two unique environments, the solvent environment and the hydration envelope (or sheath) environment. Changes to the chemical potential of H 2O in either environment result in redistribution of H 2O molecules between the environments; consequently hydration numbers of electrolytes decrease as the solvent activity decreases. An equation derived from the theory and containing two adjustable parameters reproduces electrolyte activity coefficients more accurately than does the original Stokes and Robinson equation. 相似文献
13.
Nanocomposite polymer electrolytes based on poly(ethylene glycol) diacrylate and 1 M LiBF4 solution in γ-butyrolactone containing SiO2 nanoparticles were studied by FT IR spectroscopy. Quantum chemical modeling of five different solvate complexes of ions composed of LiBF4 with solvent molecules was carried out and their theoretical IR spectra were calculated. The compositions of the solvate complexes of LiBF4 in the nanocomposite gel electrolyte were studied by comparing the experimental and theoretical IR spectra. It was concluded that the conductivity peak observed upon adding 2 wt.% SiO2 is due to the appearance of mobile ions as a consequence of ionic dissociation on the surface of nanoparticles at their optimal configuration. 相似文献
14.
The present communication reports on the preparation of polyaniline nanofibers (PANINFs) by chemical oxidative polymerization of aniline under rapid stirring using ammonium persulfate as the oxidant in acidic aqueous media in the presence of carbon nanoparticles. The subsequent treatment of such nanofiber with a AgNO 3 aqueous solution leads to in situ chemical reduction of Ag + on them to form Ag nanoparticle-decorated PANINFs. The resultant composites show good catalytic activity toward the reduction of H 2O 2. An effective enzymeless H 2O 2 sensor based on such composites is also constructed. It exhibits a fast amperometric response time 2 s, and it has a linear detection range from 0.1 to 60 mM and detection limit of 0.9 μM at a signal-to-noise ratio of 3, respectively. 相似文献
15.
On the basis of a method of differences of Volta-potentials at 298.15 K the real primary effect of an environment of cadmium ions and the real Gibbs energy for the transport of Cd 2+ out of water into a water-acetone solvent (Me 2CO) are determined. The surface potential at the nonaqueous solvent/gas phase interface \(\Delta \chi _{H_2 O}^S\) is obtained. This quantity is taken into account when calculating chemical thermodynamic characteristics for cadmium ions and the surface potential at the gas phase/acetone interface \(\Delta \chi ^{\operatorname{Me} _2 \operatorname{O} } = - 0.337\operatorname{V}\). Thermodynamic characteristics of the over-solvation of a II-I electrolyte with those for a I-I electrolyte are compared. 相似文献
16.
The Gemini surfactant 9B-4-9B containing sodium sulfonate as hydrophilic head group was synthesized based on nonylphenol and characterized by FTIR, 1H NMR spectroscopy and the surface tension measurement. The CMC and C 20 of the 9B-4-9B were smaller than that of sodium dodecylbenzene sulfonate and sodium dodecylsulfate, respectively, indicating excellent efficiency of micelle formation and reduced surface tension. Conducting polyaniline salts were synthesized by chemical oxidative micellar polymerization of aniline in water firstly using Gemini surfactant 9B-4-9B as the micelle stabilizer and ammonium peroxydisulfate as the oxidant at 0 °C. The stable polyaniline dispersions have been obtained when the molar ratio of the 9B-4-9B to aniline was equal to or above 0.5 used in the polymerization system. The obtained granular polyaniline particles with the size of 1-2 μm were characterized by FTIR, UV-Vis, SEM, WAXD and conductivity measurement. 相似文献
17.
Electrochemical copolymerization of phenol and aniline was achieved on 304 stainless steel anodes in neutral water solution with an electrolyte of Na 2SO 4O 4. Compared with pit corro-sion potential of different copolymer coatings, the best solution composition was 0.09 mol/L phenol and 0.01 mol/L aniline. Through infrared spectrum analysis, polyaniline structure was proved in phenol-aniline copolymer, as well as more side chains. Scanning electron mi-croscope was used to analyze microstructure of copolymer coating, taking advantage of part solubility of phenol-aniline copolymer in tetrahydrofuran, the bifurcate network structure was observed. The copolymer coating microstructure was summarized, compared with the performance of polyphenol coatings, the reasons of corrosion resistance enhancement with the addition of aniline in electropolymerization reaction was assumed as well. 相似文献
18.
Conducting composite systems containing polyaniline layers produced on the surface and inside the pores of polyethylene support have been prepared. Microporous polyethylene films were obtained by melt extrusion with subsequent annealing, uniaxial extension, and thermal fixation. Polyaniline layers were formed by in-situ polymerization of aniline onto polyethylene porous support placed into the aqueous reaction mixture. Structural and chemical transformations upon heating of these systems in air in free state and in vacuum under load have been investigated by thermo-mechanical tests, IR spectrometry, and electron microscopy. Changes in mechanical properties of composites after heating have been analyzed. Composite systems have been found to demonstrate a considerably lower shrinkage upon heating than microporous polyethylene substrates. It has been discovered that the composites preserve mechanical integrity on heating up to temperatures much higher than the polyethylene melting point. It is concluded that thermo-mechanical behaviour of the composites is determined by the space-continuous phase of polyaniline on the surface and in the bulk of polyethylene support. 相似文献
19.
The solvolysis of the [Cr(NCS) 4(aniline) 2] ? complex ion has been studied in various acetone-water mixtures in the presence of perchloric acid (10 ?3–10 ?1 mole/l). In acid solutions the first two NCS ? ions are exchanged, presumably, for water molecules and in parallel an aniline molecule for acetone, the latter in a second order reaction, accelerated by hydrogen ions. The exchange of the amine is followed by the substitution of the first two NCS ? ions. The third and fourth NCS ? ions are substituted only in neutral or weakly acid solutions. Kinetic parameters have been derived for the reactions mentioned above. The influence of solvent composition and of acidity is discussed. 相似文献
20.
Ruthenium(III) trichloride microcrystals were soaked in aniline and aniline/acetonitrile mixtures. In all cases, polyaniline
(PANI) was formed as a result of the intercalation of aniline into the layered structure of RuCl 3 crystal and the reaction between aniline and the host material. The appearance of polyaniline was proven by infrared spectroscopy.
The as-formed (PANI)
x
z+(RuCl 3)
y
z− nanocomposites were attached to gold surfaces and studied by cyclic electrochemical nanogravimetry. The sorption of aniline
and its effect on the nanocomposites immobilized on gold were also studied in supporting electrolytes. The redox behaviour
of the composite shows the electrochemical transformations of both polyaniline and RuCl 3. The redox waves of PANI are similar to those observed for very thin PANI films. It attests that the response is originated
from monolayer-like PANI film situated between RuCl 3 layers. The transport of the charge-compensating ions reflects the variation of the oxidation states of both PANI and RuCl 3. The nanocomposites behave as self-doped layers in the potential region when both constituents are charged, i.e. PANI is
partially oxidized while RuCl 3 is partially reduced, since the electroneutrality is assured by mutual charge compensation. When PANI is reduced, cations
enter the layer to counterbalance the negative charge resulting from the reduction of Ru(III) to Ru(II). It was also found
that the intercalation of water molecules is—albeit still substantial—smaller than that of pure RuCl 3 microcrystals, which is related to the presence of PANI between the RuCl 3 layers.
Dedicated to Prof. Mikhail A. Vorotyntsev on the occasion of his 60th birthday 相似文献
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