Chemical Oxidative Polymerization Of Pyrrole Research Articles

Polypyrrole nanoparticles with high dispersion stability via chemical oxidative polymerization in presence of an anionic–non-ionic bifunctional polymeric surfactant

Formation of colloidal dispersions is the most attractive and efficient method which can improve the inherent insoluble and intractable properties of polypyrrole. Polyoxyethylene nonylphenyl ether sulfate (NPES), a novel bifunctional polymeric surfactant which has both anionic and non-ionic active groups, was used as both the template and the dopant in the chemical oxidative polymerization of pyrrole in the present work. The size of the NPES doped polypyrrole nanoparticles (PPy/NPES) decreased and their water-dispersion stabilities increased with the increasing of the feeding ratio of NPES. The PPy/NPES nanoparticles possess high electrical conductivity at room temperature and the weak temperature dependence of the conductivity. The conductivity–temperature heating curves are discussed.

Acid blue AS doped polypyrrole (PPy/AS) nanomaterials with different morphologies as electrode materials for supercapacitors

The polypyrrole (PPy) nanomaterials with different morphologies were prepared via the chemical oxidative polymerization of pyrrole in the presence of acid blue AS (AS) as the dopant and surfactant. Increasing of the feeding ratio of AS, the morphology of the resultant acid blue AS doped polypyrrole (PPy/AS) nanomaterials changed from nanoparticles to clusters of nanofibers and nanoparticles, then nanorods, compared with the microsized PPy particles prepared without AS. The PPy/AS with the morphology of the clusters of nanofibers and nanoparticles (S-3) showed the highest electrical conductivity of 20S/cm. When the PPy/AS samples was used as the electrode materials for the supercapacitors, two redox processes were observed in the cyclic voltammograms (CV) of all the PPy/AS electrodes, corresponding to the redox couples of AS. The highest specific capacitance was found to be 427F/g with the PPy/AS S-3 sample.

Electrochemical and TOF-SIMS investigations of PPy/PEG-modified LiFePO 4 composite electrodes for Li-ion batteries

The role of polyethylene glycol (PEG) in mixed polypyrrole (PPy) polymer blend for new cathode material used in Li-ion battery has been studied. The films of PPy containing PEG were prepared by chemical oxidative polymerization of pyrrole (Py) monomer. PEG has been applied as an additive during polymerization process to improve mechanical and structural properties of PPy in final PPy/PEG–LiFePO 4 cathode material aiming also better electronic conductivity. The electrochemical behavior of the samples was examined by galvanostatic charge/discharge technique and cyclic voltammetry (CV). It was found that PPy/PEG blend polymer decreases the contact resistance and improves the Li + intercalation/deintercalation during cycling. Charge/discharge measurements confirmed the increase in capacity when applying PEG in PPy. Time of flight secondary ion mass spectrometry (TOF-SIMS) analysis confirmed supporting effect of PEG in PPy predominantly for mixed polymer mechanical stability (important at charging cycles). Distribution of PPy, PEG and Li + fragments within blended polymer films were monitored by measuring the intensities of different secondary ions, applying SIMS.

Well-Defined Core−Shell Carbon Black/Polypyrrole Nanocomposites for Electrochemical Energy Storage

The well-defined core-shell carbon black/polypyrrole (CB/PPy) nanocomposites were prepared via the in situ chemical oxidative polymerization of pyrrole from the surfaces of the carbon black (CB) nanoparticles, with poly(2-hydroxy-3-(methacryloyloxy) propane-1-sulfonate) (PHMAS) as both the surfactant and the dopant. The nanocomposites exhibited the high conductivity at room temperature and the weakly temperature dependence of conductivity from 283 to 423 K. When the core-shell CB/PPy nanocomposites were used as the electrode materials for the supercapacitors, the maximum discharge capacity of 366 F/g was achieved, after being corrected for the weight percentage of the PPy phase at the current density of 5 mA/cm(2) in 1.0 M NaNO(3) electrolyte solution.

MnO2/PPy/PANI三元纳米管复合材料的合成及其电化学电容性能

在聚苯胺（PANI）和二氧化锰（MnO2）存在的条件下，以FeCl3／甲基橙为模板，通过化学氧化法聚合吡咯（Py）单体，制备MnO2／PPy／PANI纳米管复合材料。利用X射线衍射、透射电子显微镜、红外光谱和电化学测试等多种测试技术对复合材料进行物性表征和电化学电容性能测试，并讨论了不同含量的PANI对复合物材料的结构和性能的影响。结果表明，由于PANI、MnO2与PPy三者的相互协同作用，以及材料管状结构的大比表面积，使三元复合材料具有比二元复合材料要大的电化学活性。所合成的三元复合材料最大比容量达到458．4F／g。

Well-defined polypyrrole nanoflakes via chemical oxidative polymerization in the presence of sodium alkane sulfonate

The conductive polymers with unique nanostructures have attracted intense interest due to their potential application. Here the well-defined polypyrrole nanoflakes (PPy/AS) were fabricated via the facile chemical oxidative polymerization of pyrrole with high feeding ratio of sodium alkane sulfonate (SAS). SAS was used as the surfactant (template) and dopant for the nanostructured conductive polymer for the first time. The morphology of the products changed from particles to nanoflakes with the increasing of the feeding ratio of SAS. The polypyrrole nanoflakes (PPy/AS) were characterized with Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and electrical conductivity techniques. They exhibited the weak electrical conductivity dependence on temperature.

Facile synthesis of electroactive polypyrrole–chitosan composite nanospheres with controllable diameters

AbstractPolypyrrole–chitosan composite (PCC) nanospheres with uniform diameters have been synthesized by in situ chemical oxidation polymerization of pyrrole in chitosan aqueous solution. The influences of synthetic parameters, such as the concentrations of chitosan and pyrrole, and types of oxidants on the diameters and molecular structures of the PCC nanospheres have been investigated. It is found that the diameters of the PCC nanospheres can be controlled by adjusting the concentrations of chitosan and pyrrole. Chitosan is absorbed on/in polypyrrole nanospheres to form the PCC nanospheres. The resulting PCC nanospheres preserve both the electroactivity of polypyrrole and the biocompatibility and bioactivity of chitosan, and may have potential biomedical applications such as in biosensors and in the controlled release of drugs. Copyright © 2010 Society of Chemical Industry

Facile preparation and characterization of copolymer nanoparticles from pyrrole and aniline-2-sulfonic acid

Novel poly(pyrrole-co-aniline-2-sulfonic acid) (PPYAS) nanoparticles were prepared via chemical oxidative polymerization of pyrrole and aniline-2-sulfonic acid in different aqueous solutions without any external additives. The morphology, structure and electroconductivity of the HCl-doped particles were studied by changing the molar ratio of the oxidant and monomers, and the solvent for polymerization. It was found that the yield, mean diameter and electrical conductivity of the resulting particles varied strongly with the molar ratio of the components. The nanoparticles exhibit a minimum mean diameter of around 62 nm, and good self-stability because of the introduction of sulfo groups into the chains of the copolymer. The preparation affords yield of up to 85%, and the HCl-doped copolymer salts possess an electroconductivity between 0.68 and 0.2 S/cm, depending on the fraction of anilinesulfonic acid.

Water-dispersed polypyrrole nanoparticles via chemical oxidative polymerization in the presence of a functional polyanion

Poly(2-hydroxy-3-(methacryloyloxy) propane-1-sulfonate) (PHMPS), a polyhydroxyl sulfonate, was used as both the template and the dopant in the in situ doping chemical oxidative polymerization of pyrrole. The resultant PHMPS doped polypyrrole (PPy/PHMPS) nanoparticles were characterized with FTIR, UV–vis, TGA, zeta potentials and TEM techniques. It was found that their size decreased and their dispersing stabilities in water increased with the increasing of the feeding ratio of PHMPS. The PPy/PHMPS nanoparticles possess high electrical conductivity at room temperature and the weak temperature dependence of the conductivity. The conductivity–temperature heating curves are discussed.

Preparation and electrochemistry of one-dimensional nanostructured MnO 2/PPy composite for electrochemical capacitor

One-dimensional nanostructured manganese dioxide/polypyrrole (MnO 2/PPy) composite was prepared by in situ chemical oxidation polymerization of pyrrole in the host of inorganic matrix of MnO 2, using complex of methyl orange (MO)/FeCl 3 as a reactive self-degraded soft-template. The morphology and structure of the composite were characterized by infrared spectroscopy (IR) X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the MnO 2/PPy composite consists of α-MnO 2 and PPy with nanotube-like structure. Electrochemical properties of the composite demonstrated the material showed good electrochemical reversibility after 500 charge–discharge cycles in the potential range of −0.4 to 0.6 V, the tube-like nanocomposite has the potential application in electrochemical capacitor.

Preparation and Characterization of Conjugated Polypseudorotaxane Poly(Pyrrole/α-Cyclodextrin)

Conjugated polypseudorotaxane polypyrrole/α-cyclodextrin (PPy/α-CD) was synthesized by chemical oxidative polymerization of pyrrole in the presence of α-CD. The FT-IR spectra and wide-angle X-ray diffraction (WAXD) pattern showed that the pyrrole-CD (Py-CD) rotaxanes were presented in the polypyrrole (PPy) chains. The polypseudorotaxane wires composed of α-CD as the insulating cover and polypyrrole as the core were expected product in this study. The elemental analysis suggests that the molar ratio of α-CD to pyrrole is 1:5. Because of the discontinuous presence of Py-CD rotaxanes, the conductive behavior morphology and thermal stability of the polypseudorotaxanes are greatly different than those of the pure PPy. Moreover, this work analyzed the reaction mechanism in the microscopic view.

PPy doped PEG conducting polymer films synthesized on LiFePO 4 particles

In this work, polyethyleneglycole (PEG) is introduced into polypyrrole (PPy) film coated on LiFePO 4 powder particles to promote the properties of cathode material for lithium-ion batteries. The enhancement of the electrochemical activity by the substitution of a carbon with electrochemically active polymer is investigated. Films of the PPy doped with the PEG were prepared by the chemical oxidative polymerization of pyrrole (Py) monomer. PEG has been added as an additive during polymerization process to improve mechanical and structural properties of the PPy in final PPy/PEG–LiFePO 4 cathode material. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge measurements were employed to characterize the electrochemical properties of PPy/PEG–LiFePO 4 material. The electrochemical performance of PPy–LiFePO 4 electrodes was greatly improved by introduction of PEG into the PPy films. Charge/discharge measurements confirmed the increase in capacity when applying PEG in PPy. The morphology and particle sizes of the prepared cathode powder material were investigated by scanning electron microscopy (SEM) and particle size analysis (PSA). Distribution of PPy and PPy/PEG films onto the LiFePO 4 particles surface was studied by time of flight secondary ion mass spectrometry (TOF-SIMS). In addition to polymeric coating layer on the surface of PPy–LiFePO 4 composite particles, some PPy unequally distributed between the particles was found. The median diameter value is 4.92 μm for PPy–LiFePO 4 sample. TOF-SIMS measurements and SEM images confirmed that thickness of polypyrrole coating on LiFePO 4 particles is about 100 nm.

Water-dispersed polypyrrole nanospheres via chemical oxidative polymerization in the presence of castor oil sulfate

The castor oil sulfate (COS), produced by the sulfonation of the castor oil (one of the most promising renewable sources), was used as both the surfactant and the dopant in the chemical oxidative polymerization of pyrrole. The resulting castor oil sulfate doped polypyrrole nanospheres (PPy/COS) were characterized with FTIR, UV–vis, TGA, zeta potentials and TEM techniques. It was found that their diameter decreased and their dispersing stabilities in water increased with the increasing of feeding ratio of COS. The PPy/COS nanospheres possess high electrical conductivity at room temperature and the weak temperature dependence of the conductivity.

Efficient Synthesis of Intrinsically Conducting Polypyrrole Nanoparticles Containing Hydroxy Sulfoaniline as Key Self-Stabilized Units

Self-stabilized copolymer nanoparticles are easily and productively synthesized by a chemical oxidative polymerization of pyrrole (Py) and 2-hydroxy-5-sulfonic aniline (HS) in 1 M HCl without any external template. UV−vis, IR, 1D 1H NMR, 2D 1H−1H COSY NMR, and 2D 1H−13C HSQC NMR all indicate that a real copolymerization occurs between HS and Py comonomers and Py units construct the main position of the copolymer. On the basis of the elemental analysis, the reactivity ratios of HS and Py comonomers are calculated to be 0.043 and 1.14, respectively. The polymerization yield, size, morphology, and electrical conductivity of the copolymer particles can significantly be optimized by the comonomer ratio, polymerization temperature, and ammonium persulfate oxidant/comonomer ratio. The copolymer particles always keep narrow size distribution with a small polydispersity index (PDI) of 1.05−1.08. HS/Py(50/50) copolymer nanoparticles synthesized at 0 °C are found to generally have irregular granular morphology with the smallest diameter of 35−60 nm and the lowest PDI of 1.05 by laser particle-size analyzer, FE-SEM, and TEM. The mechanisms of the formation and intrinsic self-stabilization of the nanoparticles are proposed based on the powerful static repulsion from negatively charged sulfonic and hydroxyl groups on the nanoparticles. Through simple dedoping and redoping procedures, the copolymer particles exhibit a widely adjustable conductivity from 10−9 to 1.12 S cm−1. These copolymer nanoparticles show high conductivity, good self-stability, and powerful redispersibility in water and organic media. Nanocomposite films of the copolymer nanoparticles in polyvinylalcohol possess a low percolation threshold down to 0.09 wt % as well as retain 80−95% transparency and 102−108 times the conductivity of the pure polyvinylalcohol film in the nanoparticle loading from 0.09 to 3 wt %.

Structural and electrochemical studies of PPy/PEG-LiFePO 4 cathode material for Li-ion batteries

A simple chemical oxidative polymerization of pyrrole (Py) directly onto the surface of LiFePO 4 particles was applied to the synthesis of polypyrrole-LiFePO 4 (PPy-LiFePO 4) powder. The LiFePO 4 sample without carbon coating was synthesized by a solvothermal method. The polyethylene glycol (PEG) was used as additive during Py polymerization for increasing the PPy-LiFePO 4 conductivity. Properties of resulting LiFePO 4, PPy-LiFePO 4 and PPy/PEG-LiFePO 4 samples were characterized by XRD, SEM, TGA and galvanostatic charge–discharge measurements. These methods confirmed the presence of polypyrrole on LiFePO 4 particles and its homogeneous distribution in the resulting powder material. The PPy/PEG-LiFePO 4 composites show higher discharge capacity than pure LiFePO 4, as PPy/PEG network improves the electron conductivity. It presents specific discharge capacity of 153 mAh/g at C/5 rate.

Synthesis of ordered spiral and ring-like polypyrrole nanowires in cetyltrimethylammounium bromide crystalline suspension

Spiral dislocation morphology on the surface of cetyltrimethylammounium bromide (CTAB) crystallites has been discovered for the first time. By addition of ammonium peroxydisulfate into CTAB crystalline suspension, a drastic change in the morphology of result crystallites is observed from spiral to two dimensional (2D) islands. The spiral and 2D-island structures of these crystallites could be use as the templates for the synthesis of spiral and ring-like polypyrrole (PPy) nanowires, respectively, via direct chemical oxidative polymerization of pyrrole due to the oxidation reaction occurring preferentially at the steps of these crystallites. The mechanism of adsorption of pyrrole oligomers on the steps of these crystallites is proposed for the growth of PPy spiral and ring-like nanowires.

Nanostructured polystyrene-block-poly(4-vinyl pyridine)(pentadecylphenol) thin films as templates for polypyrrole synthesis

Abstract Polypyrrole has been chemically synthesized on thin film nanostructures obtained from comb-shaped supramolecules of polystyrene-block-poly(4-vinyl pyridine) (PS-b-P4VP) hydrogen bonded with pentadecylphenol (PDP). PDP was washed from thin films of cylindrical and lamellar self-assembled comb-copolymer systems, which resulted in removal of the upper layers of microdomains, leaving single cylindrical and lamellar layers covering a substrate, with P4VP segregated at the bottom as well as at the free air interface. This P4VP was complexed with Cu2+ ions, after which chemical oxidation polymerization of pyrrole resulted in a thin polypyrrole layer covering the nanostructured block copolymer. The use of a catalytic amount of bipyrrole greatly improved the quality of the obtained product. The conductivity was measured to be ∼0.7 S cm−1.

Direct Determination of Uric Acid in Human Serum Samples Using Polypyrrole Nanoelectrode Ensembles

Polypyrrole (PPy) nanotubes have been synthesized by chemical oxidative polymerization of pyrrole within the pores of polycarbonate membrane using the technology of diffusion of solutes. The nanotubes array prepared by the proposed method can be considered as nanoelectrode ensembles (NEEs). An amperometric uric acid sensor based on PPy NEEs has been developed and used for determination of uric acid in human serum samples. The electrode can direct response to uric acid at potential of 0.60V vs. SCE with wide linear range of <TEX>$1.52{\times}10^{-6}\;to\;1.54{\times}10^{-3}\;M.\;The\;detection\;limit\;is \;3.02{\times}10^{-7}$</TEX> M. This sensor has been used to determine uric acid in real serum samples. PPy NEEs is thought of as a good application in the foreground.

Synthesis and characterization of core-shell nanostructured PPy/V 2O 5 composite

Polypyrrole/V 2O 5 (PPy/V 2O 5) composite was synthesized successfully by in-suit chemical oxidation polymerization of pyrrole in the host of inorganic matrix, using complex of methyl orange (MO)/FeCl 3 as a reactive self-degraded soft-template. The morphology and molecular structure of the composite were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) transmission spectra, X-ray diffraction analysis (XRD) and thermogravimetric analysis (TGA). The results indicated that PPy/V 2O 5 composite possessed the typical core-shell nanostructures, in which the irregularly shaped V 2O 5 particles act as the “core”, while the self-assembled PPy nanotubes serve as the “shell” of the composite. And there was no obvious chemical interaction but some physical interaction between PPy and V 2O 5 in the composite.

Improved lithium exchange at LiFePO4 cathode particles by coating with composite polypyrrole–polyethylene glycol layers

The polypyrrole–LiFePO4 composites were synthesized by simple chemical oxidative polymerization of pyrrole (Py) monomer directly on the surface of LiFePO4 particles. Properties of resulting polypyrrole–LiFePO4 (PPy-LiFePO4) samples (especially conductivity) are strongly affected by the preparation technique, polymer additives, and conditions during synthesis. For increasing of PPy-LiFePO4 conductivity, we used polyethylene glycol (PEG) as additive during polymerization. The electrochemical behavior of the samples was examined by cyclic voltammetry and electrochemical impedance spectroscopy. It was found that PPy/PEG composite polymer decreased the particle to particle contact resistance. Impedance measurements showed that the coating of PPy/PEG significantly decreases the charge transfer resistance of LiFePO4 electrodes.