PANI) And Polypyrrole Research Articles

Effect of the Oxidant/Monomer Ratio and the Washing Post-Treatment on Electrochemical Properties of Conductive Polymers

Polyaniline (PANI) and polypyrrole (PPy) were prepared via the chemical oxidative polymerization with various oxidant/monomer initial mole ratios (O/M) in hydrochloric acid aqueous solution and washing with water or ethanol to investigate the effect of the O/M ratio and the washing process on their electrochemical performance as electrode materials for supercapacitors. Their morphologies were characterized with transmission electron microscopy (TEM), and the electrochemical performance of the PANI and PPy electrodes was studied by cyclic voltammogram and galvanostatic charge/discharge tests. It was found that the electrical conductivities and specific capacitances of the polymers were mainly dependent on the O/M ratio. An additional post-treatment of washing was considered as an unfavorable processing with the decrease in yield, conductivity, and capacitance, except for the partial enhancement of the cyclic stabilities. This understanding will lead to a better design of conductive polymer-based electrode ...

Electrical Coupling of Organic/Inorganic Semiconductor Interfaces: A Comparative Study

The present work attempts to investigate the interfacial phenomenon occurring between two dissimilar materials and in particular organic and inorganic hybrid materials. Layer by layer hybrid heterostructures are fabricated by electro-deposition technique. Here, ZnO thin films are deposited using potentiostatic mode using regulated DC voltage supply fixed at-1.0 V (with respect to the reference electrode) with platinum sheet (99.99% purity) used as the counter electrode and ITO-coated glass used as a working electrode. The as obtained ZnO films are then used as substrates for deposition of organic layer. Two conducting polymers namely polyaniline (PANI) and polypyrrole (PPy) are deposited by electro-deposition method on ZnO to form ZnO/PANI and ZnO/PPy interfaces. The two interfaces are compared for their photoconducting response. These studies are further correlated with the properties that the two interfaces share.

Conductive polymer‐coated mesh films with tunable surface wettability for separation of oils and organics from water

ABSTRACTHere, we reported the preparation of hydrophobic mesh films by coating conductive polymers including polyaniline and polypyrrole (PPy) onto stainless steel grid through a simple electrodepositing process by combination with modification of hydrophobic materials. The hydrophobic mesh films can be used for continual separation of oils and organics from water with high selectivity. Furthermore, mesh film with reversible switching wettability from hydrophobicity to hydrophilicity can be obtained by electrodepositing of PPy in the presence of perfluorooctanesulfonate dopants at different electric potential, which makes it possible to prepare functional mesh materials with remotely controllable surface wettability for selective absorption and purification. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40759.

Efficient quasi-solid-state dye-sensitized solar cells employing polyaniline and polypyrrole incorporated microporous conducting gel electrolytes

With an aim of elevating liquid electrolyte loading, ionic conductivity, and electrocatalytic activity of gel electrolyte toward triiodides, freeze-dried microporous poly(acrylic acid)–poly(ethylene glycol) (PAA–PEG) matrix is employed to uptake conducting polymers, such as polyaniline (PANi) and polypyrrole (PPy). An ionic conductivity of 19.18 mS cm−1 at 65 °C is obtained from PAA–PEG/PANi conducting gel electrolyte which is nearly similar to 19.22 mS cm−1 from pure liquid electrolyte. The conducting polymers can form interconnected channels within insulating microporous PAA–PEG matrix, therefore, the reduction reaction of triiodide ions in the dye-sensitized solar cells (DSSCs) can be extended from Pt/gel electrolyte interface to both interface and three-dimensional framework of microporous conducting gel electrolyte. The resultant DSSCs from PAA–PEG/PANi and PAA–PEG/PPy conducting gel electrolytes display power conversion efficiencies of 7.12% and 6.53%, respectively, which are much higher than 5.02% from pure PAA–PEG-based DSSC. The new concept along with easy fabrication promises the microporous conducting gel electrolytes to be good alternatives in efficient quasi-solid-state DSSCs.

Controlled synthesis, core–shell structures and electrochemical properties of polyaniline/polypyrrole composite nanofibers

An efficient approach was presented to prepare composite nanofibers by in situ chemical polymerization of pyrrole in the presence of polyaniline (PANi) nanofibril seeds for integrating the excellent properties of PANi and polypyrrole (PPy). The effects of PPy shell thickness on the morphology, structure and properties of the composite nanofibers have been studied by scanning electron microscopy, Fourier transform infrared spectrometry, wide angle X-ray diffractometry, thermal gravimetric analysis and electrochemical measurement. It is found that more planar conformation of PPy could be formed due to strong π–π interactions between the PANi core and the PPy shell. As a result, the efficient charge transport along the nanofiber orientation and charge transfer between the core and shell of the composite nanofibers can be facilitated. Furthermore, compared with neat PANi and PPy, great improvements in electrical and electrochemical properties for the composite nanofibers can be achieved due to their unique configuration and synergistic contribution.

Magnetoresistive conductive polymer-tungsten trioxide nanocomposites with ultrahigh sensitivity at low magnetic field

The effect of conductive polymer matrix including polyaniline (PANI) and polypyrrole (PPy) on the magnetoresistance (MR) behaviors in the variable range hopping (VRH) regime has been investigated in the disordered polymer nanocomposites containing tungsten trioxide (WO3) nanoparticles. These nanocomposites have demonstrated ultrahigh MR sensitivity at low magnetic field regime. The observed positive MR has been well explained by the wave-function shrinkage model. The conductive polymer matrix has shown different effects on the MR behaviors of the nanocomposites. The WO3/PANI nanocomposites have a lower localization length (a0) and density of states at the Fermi level (N(EF)), and higher average hopping distance (Rhop) and average hopping energy (W) compared with those of the WO3/PPy nanocomposites.

Study of the Preparation and Property of Oxygen Reduction Electrode Based on Polyaniline or Polypyrrole

Polyaniline (PANI) and polypyrrole (PPy) is developed rapidly with special physical and chemical performance. According to high catalytic activity, polyaniline is applied in a wide range of electrocatalysis area, especially for oxygen reduction. In this paper, electrochemical prepared polyaniline was used as catalyst as well as the loading of noble metal catalyst for manufacturing oxygen reduction electrode. Then the influence of carrier, noble metal and their binding forms to the ability of oxygen reduction were investigated by cyclic voltammeter. The result shows that PANI carrier was the most influential factor for oxygen reduction; for single noble metal catalyst, Pt shows bigger catalytic activity than Ag. And the best catalytic activity was optimized at dual deposited catalyst as Ag, Pt mass ratio to 23:100. Further more; compared to glassy carbon, graphite is much better for electrode basement.

Carbonised polyaniline and polypyrrole: towards advanced nitrogen-containing carbon materials

AbstractPolyaniline (PANI) and polypyrrole (PPY) undergo carbonisation in an inert/reduction atmosphere and vacuum, yielding different nitrogen-containing carbon materials. This contribution reviews various procedures for the carbonisation of PANI and PPY precursors, and the characteristics of obtained carbonised PANI (C-PANI) and carbonised PPY (C-PPY). Special attention is paid to the role of synthetic procedures in tailoring the formation of C-PANI and C-PPY nanostructures and nanocomposites. The review considers the importance of scanning and transmission electron microscopies, XPS, FTIR, Raman, NMR, and EPR spectroscopies, electrical conductivity and adsorption/desorption measurements, XRD, and elemental analyses in the characterisation of C-PANIs and C-PPYs. The application of C-PANI and C-PPY in various fields of modern technology is also reviewed.

Impedance Study of Tea with Added Taste Compounds Using Conducting Polymer and Metal Electrodes

In this study the sensing capabilities of a combination of metals and conducting polymer sensing/working electrodes for tea liquor prepared by addition of different compounds using an impedance mode in frequency range 1 Hz-100 KHz at 0.1 V potential has been carried out. Classification of six different tea liquor samples made by dissolving various compounds (black tea liquor + raw milk from milkman), (black tea liquor + sweetened clove syrup), (black tea liquor + sweetened ginger syrup), (black tea liquor + sweetened cardamom syrup), (black tea liquor + sweet chocolate syrup) and (black tea liquor + vanilla flavoured milk without sugar) using six different working electrodes in a multi electrode setup has been studied using impedance and further its PCA has been carried out. Working electrodes of Platinum (Pt), Gold (Au), Silver (Ag), Glassy Carbon (GC) and conducting polymer electrodes of Polyaniline (PANI) and Polypyrrole (PPY) grown on an ITO surface potentiostatically have been deployed in a three electrode set up. The impedance response of these tea liquor samples using number of working electrodes shows a decrease in the real and imaginary impedance values presented on nyquist plots depending upon the nature of the electrode and amount of dissolved salts present in compounds added to tea liquor/solution. The different sensing surfaces allowed a high cross-selectivity in response to the same analyte. From Principal Component Analysis (PCA) plots it was possible to classify tea liquor in 3-4 classes using conducting polymer electrodes; however tea liquors were well separated from the PCA plots employing the impedance data of both conducting polymer and metal electrodes.

Bringing Conjugated Polymers and Oxide Nanoarchitectures into Intimate Contact: Light-Induced Electrodeposition of Polypyrrole and Polyaniline on Nanoporous WO3 or TiO2 Nanotube Array

This proof-of-concept study focuses on the photocatalytic electrodeposition of two conducting polymers, namely, polyaniline (PANI) and polypyrrole (PPy), in two different nanostructured inorganic semiconductor host matrices, namely, nanoporous tungsten trioxide and nanotubular titanium dioxide. Oxide semiconductor (WO3 and TiO2) films were initially electrosynthesized on tungsten and titanium foils, respectively, by anodization at different voltages in fluoride-containing aqueous media. The conjugated polymer was electrografted onto the entire surface of the photoexcited oxide semiconductor matrix using potentiostatic and potentiodynamic deposition methods. The crucial role of initial photoelectrochemical deposition, preceding the electrochemical polymerization step, was demonstrated. The photoelectrodeposited and electrodeposited hybrid samples were compared from both morphological and electrochemical perspectives. Importantly, through application of the methodology presented in this article, deposition ...

Conducting Polymers Directly Coated on Reduced Graphene Oxide Sheets as High-Performance Supercapacitor Electrodes

In this work, conducting polymers poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANi), and polypyrrole (PPy) were directly coated on the surface of reduced graphene oxide (RGO) sheets via an in situ polymerization process to prepare conducting-polymer-RGO nanocomposites with different loadings of the conducting polymers. Experiment results showed that ethanol played an important role in achieving a uniform coating of the polymers on RGO sheets. The electrochemical capacitive properties of the composite materials were investigated by using cycle voltammetry and charge/discharge techniques. The composite consisting of RGO and PANi (RGO-PANi) exhibited a specific capacitance of 361 F/g at a current density of 0.3 A/g. The composites consisting of RGO and PPy (RGO-PPy) and PEDOT (RGO-PEDOT) displayed specific capacitances of 248 and 108 F/g, respectively, at the same current density. More than 80% of initial capacitance retained after 1000 charge/discharge cycles, suggesting a good cycling stability ...

STUDY OF CO-ASSEMBLED CONDUCTING POLYMERS FOR ENHANCED ETHANOL ELECTRO-OXIDATION REACTION

ABSTRACTHerein, we investigated the effects of polyaniline (PANI) and polypyrrole (PPY) in their native and co-assembled forms as a thin layer on Pt nanoparticle-decorated multi-walled carbon nanotubes (Pt/MWCNTs) toward the ethanol oxidation reaction (EOR). The co-assembled conducting PANI-PPY deposited Pt/MWCNTs was successfully synthesized and demonstrated significant enhancement of the electro-catalytic activity and stability toward EOR as revealed by electrochemical characterizations. The presented results indicate that in the co-assembled form, PANI and PPY retained their own superior effects on the enhancement of stability and catalytic activity via intermediate species removal and ethanol adsorption, respectively. This preliminary result reveals a new strategy for the use of conducting polymers as potential catalyst supports due to its facile fabrication and functionalization, cost effectiveness and environmental friendliness in comparison to alloys and metal oxides, factors which are necessary for the practical application of direct ethanol fuel cells in the near future.

Conducting polymer/carbon nanocoil composite electrodes for efficient supercapacitors

Herein, we report for the first time, conducting polymer (polyaniline (PANI) and polypyrrole (PPY)) coated carbon nanocoils (CNCs) as efficient binder-free electrode materials for supercapacitors. CNCs act as a perfect backbone for the uniform distribution of the conducting polymers in the composites. In two electrode configuration, the samples exhibited high specific capacitance with the values reaching up to 360 and 202 F g−1 for PANI/CNCs and PPY/CNCs respectively. The values obtained for specific capacitance and maximum storage energy per unit mass of the composites were found to be comparable to one of the best reported values for polymer coated multi-walled carbon nanotubes. In addition, the fabricated PANI/CNC based supercapacitors exhibited a high value of 44.61 Wh kg−1 for maximum storage energy per unit mass. Although the devices exhibit an initial capacitance loss due to the instability of the polymer, the specific capacitance stabilizes at a fixed value after 500 charge–discharge cycles.

Effect of Dopants on Microstructure and Properties of Polyaniline and Polypyrrole

Polyaniline (PANI) and polypyrrole (PPy) doping with hydrochloric acid (HCl), p-toluenesulfonate (pTSA) were successfully synthesized by chemical oxidation polymerization. Ammonium peroxydisulfate was used as an oxidizing agent at room temperature. Microstructure of PPy and PANI was studied by scanning electron microscopy (SEM). Discussed the acid concentration how influenced on the electrical conductivity properties of PANI and PPy, and also compared their resistivity and thermal stability. The results showed that HCl effectively improved conductive properties of PANI in a wide range concentrations, and pTSA in narrow range concentrations. When doping with HCl, the minimum volume resistivity of PANI was 0.24 Ω • cm, and PPy was about 10.5 Ω • cm. When doping with pTSA, the volume resistivity minimum of PANI was 1.3 Ω • cm, and PPy was 15.8 Ω • cm. The conductivity of PPy was weaker than PANI. The thermal stability of conducting polymers which doping with pTSA was better than which doping with HCl.

Improved microwave absorption and electrostatic charge dissipation efficiencies of conducting polymer grafted fabrics prepared via in situ polymerization

AbstractPolyaniline (PANI) and polypyrrole (PPY) were grafted over cotton fabrics by in situ polymerization. FTIR spectra show systematic shifting of bands corroborating surface grafting of conducting polymers on cotton fabric. SEM images revealed that the surface coating of PANI was smoother than PPY. However, better control over coating thickness and uniformity was achieved in PPY fabric. The probable formation mechanism of grated fabrics has also been proposed. The good thermal stability and acceptable electronic conductivity values indicate that these fabrics could be used for electrostatic charge dissipation and microwave absorption. The antistatic studies have shown complete charge dissipation (decay time <0.01 sec). The microwave absorption studies of the conducting fabrics in X‐band (8.2–12.4 GHz) show absorption dominated total shielding effectiveness in the range −11.3 to −11.7 dB (>92% attenuation) and −9.2 to −9.6 dB (>88% attenuation) for fabrics grafted with PPY and PANI, respectively. Copyright © 2011 John Wiley & Sons, Ltd.

Flexible and macroporous network-structured catalysts composed of conducting polymers and Pt/Ag with high electrocatalytic activity for methanol oxidation

Flexible and uniquely network-structured polyaniline (PANi) and polypyrrole (PPy) supported Pt and Ag catalysts were synthesized using eggshell membrane as a template and explored for the methanol oxidation reaction (MOR) for proton exchange membrane fuel cell (PEMFC) application. The scanning electron microscopy observation showed a hierarchically ordered macroporous network of PANi and PPy. Due to the difference of polymer and metal essences, Pt was in the form of nanoparticles and Ag was in the form of nanofibers on the surfaces of PANi and nanoflakes on PPy. Energy dispersive X-ray spectra, thermal gravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction patterns and X-ray photoelectron spectra were used to characterize the resultant catalysts. The results revealed that the prepared flexible catalysts had a Pt loading of 7.5 and 7.48 wt% in Pt/PANi and Pt/PPy, and a Ag loading of 11.3 and 5.78 wt% in Ag/PANi and Ag/PPy, respectively. The PANi network was in its crystalline structure, which was expected to provide very high conductivities and electrochemical properties. The cyclic voltammetric studies at room temperature showed an excellent electrocatalytic activity for MOR in acidic medium. The catalysts were also checked in the electro-oxidation of methanol at high temperatures, a much higher electrocatalytic activity at 200 °C than that at 50 °C and good stability made them potential candidates for high-temperature PEMFCs. Combined with the mechanical strength, it is believed that PANi-based catalysts are more useful in MOR applications. The excellent properties, alterable supports, simple preparation procedure and low cost allow these catalysts to be used in high-temperature PEMFCs and other fields.

Influence of Shell Layer Thickness on Electrochemical Process for Polyaniline and Polypyrrole Coaxial Nanofibers as Supercapacitor Electrode Materials

The electrochemical performance of polyaniline (PANI) and polypyrrole (PPy) coaxial nanofibers as supercapacitor electrode materials was evaluated by electrochemical impedance spectroscopy. The influence of the shell layer thickness on the charge transport and transfer process for the coaxial nanofibers in aqueous Na2SO4 solutions was studied. It is found that the existence of strong interaction between PANI and PPy, good orientation of conducting polymer chains, and large surface area to volume ratios in coaxial nanofibers are a benefit to the sufficiently diffusion of the charges, which demonstrates that the resulting nanofibers have potential application as electrode materials for supercapacitor.

Application of polyaniline and polypyrrole composites for paper mill wastewater treatment

This paper deals with a new application of polyaniline (PAn) and polypyrrole (PPy) synthesized chemically. Coated on sawdust via cast method the polypyrrole/sawdust (PPy/SD) and polyaniline/sawdust (PAn/SD) were used as effective adsorbents for the removal of heavy metals, anions, color and COD (chemical oxygen demand) from mill paper wastewater. The products were investigated in terms of morphology and chemical structure using scanning electron microscopy and Fourier-transform infrared spectroscopy (FTIR), respectively. It was found that PPy/SD and PAn/SD are very simple to prepare and can be used as effective adsorbents in the removal of anions, heavy metals, color and COD from paper mill wastewater.

Synthesis, Properties and Applications of Conducting Polymer Nano-Objects

Two different approaches are used to produce conducting polymer nano-objects. One is a “top-down” approach which involves laser ablation of conducting polymer films using laser light interference patterns (direct laser interference patterning, DLIP) to produce various surface shapes, including nanowires and nanodots. Polyaniline(PANI) and polypyrrole (PPy) nanostructures could be easily produced by ablation of films, previously formed by in-situ polymerization of the aromatic monomers. The other is a “bottom-up” approach involving the controlled nucleation and growth during monomer polymerization. This is achieved by performing the polymerization at the interface of two immiscible solvents. Both kinds of nanomaterials are characterized using dynamic light scattering, TEM, EDAX, FTIR, UV-vis and fluorescence spectroscopy. The structures are studied by SEM-FIB, optical and fluorescence microscopy along with water contact angle. It is shown that nanometric sized structures can be made by both methods. The chemical structures are quite similar or identical to that of the bulk polymer. While PANI nanofibers are dispersed in acid media, due to the surface charge related with chain protonation, they agglomerate in neutral media. In the interest of biological applications, different soluble polymers are used to help disperse the nanofibers at neutral pH. Both the dispersing agent and PANI nanofibers have to be innocuous to biological cells and higher organisms, like frog larvae. The successful intake of PANI nanofibers into cancer line cells and frog larvae prompts its application as NIR radiation absorbers in photothermal or photoacoustic tumor therapy and/or tomography.

Biological templating of polyaniline and polypyrrole using E. coli

This study evaluated a simple method for preparing microstructures of polyaniline (PANI) and polypyrrole (PPy) using a different concentrations of Escherichia coli (E. coli) as a biological template. Scanning electron microscopy and transmission electron microscopy revealed fibers, cones/spheres, and agglomerated fiber structures with dimensions ranging from 0.5 to 1 μm. The results yielded structures with shapes that varied according to the E. coli concentration. Based on these results, this study suggests that the biological templating approach can be a superior alternative to preparing and fabricating conducting polymers that may be useful for obtaining nano- or micromaterials and devices.