Study of Polypyrrole Films Modified with Copper and Silver Microparticles by Electrochemical Cementation Process (original) (raw)
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Electrodeposition of copper into functionalized polypyrrole films
Journal of Electroanalytical Chemistry, 1999
Copper microparticles have been dispersed in anion-exchange polymer films coated on carbon electrodes by oxidative electropolymerization of pyrrole-alkylammonium monomers. Incorporation of copper in polymeric films was effected by impregnation of copper-oxalate anionic complexes followed by an electroreductive precipitation to copper metal, or by electroreduction of polymer coated electrodes immersed in copper-oxalate aqueous solutions. The deposition process was examined by voltammetry. Scanning electron microscopy showed a dispersion of metal particles from 50-100 up to 300 nm, according to the lipophilic character of the polymer, located in a layer near the carbon polymer interface. A study of the electrocatalytic activity in the reduction of nitrobenzene to aniline at these materials was performed. The cathodes appeared much more active than bulk copper electrodes.
Study of the Properties of Electrodeposited Polypyrrole Films
Russian Journal of Electrochemistry, 2004
Experimental and theoretical methods have been used for characterization of the properties of polypyrrole films. The AFM studies show that the morphology of polypyrrole (PPy) films on polycrystalline gold electrodes at the first stages of synthesis depends on the structure of the metal surface. It was established that mobility of anions depends remarkably on the rate of electrodeposition of the polymer film. If PPy film was deposited at relatively low current density, mobility of anion was not high enough to guarantee electroneutrality during redox cycling and cations take part in this process especially when Li + cations were replaced by more mobile ä + cations. Semiempirical (AM1 and PM3) quantum-chemical methods were used for theoretical studies. It was established that different size and charge of the anions together with the variation in doping levels give rise to a different optimal conformation of oligopyrrole cations which, in turn, define the resulting polymer to be either all-anti (common linear chains) or all-syn (formation of helical structures) or a combination of the two.
Lancet, 2011
Polypyrrole films were electrosynthesized on conductive tin oxide substrates by potentiostatic deposition in various aqueous electrolyte solutions including p-toluenesulfonate, naphthalenesulfate, nitrate, tetrafluoroborate, and perchlorate anions. Electrical and structural characteristics (morphology, roughness and thickness) were determined using Van der Pauw method, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Optical Profilometry (OP). Experimental parameters including the electrolyte, applied electrodeposition potential, and pyrrole concentration were shown to affect the morphologies and conductivities of so-prepared polypyrrole films. The p-toluenesulfonate doped polypyrrole film showed the highest conductivity whereas the perchlorate doped one showed the lowest conductivity of all the films. On the contrary, the film thickness did not affect the electrical conductivity. Concerning the morphology, globular-shaped topographic structures were obtained for nearly all the polymer films, but with different sizes of globules and aggregates. Both roughness and morphological features were also proved to be very dependent from the electropolymerization parameters.
Electrochemically deposited polypyrrole films and their characterization
Surface & Coatings Technology, 2007
Ionically conductive polypyrrole films have been deposited at 295 K from anhydrous acetonitrile, acetonitrile/H 2 O and NaBF 4 aqueous solutions onto platinum, mild steel and stainless steel discs, using cyclic voltammetry, potentiostatic and galvanostatic techniques. Cyclic voltammetry of the polymer films has been studied as a function of water content of the acetonitrile solvent, polypyrrole concentration and potential sweep rate. Potentiostatic growth of thicker (b 30 micron) films on stainless steel allowed free-standing polypyrrole membranes to be produced. Well adherent and conductive films were deposited at constant potential in stirred solutions from acetonitrile electrolytes containing 1% (v/v) of water. The membrane resistivity of the reduced films in 0.5 mol dm − 3 KCl (aq) at 295 K was ≈1 × 10 6 Ω cm, while the resistivity of the oxidised membrane was 2700 Ω cm.
Electrochemical activity of chemically deposited polypyrrole films
Journal of Solid State Electrochemistry, 2003
Conducting polypyrrole (PPY) films are deposited on platinum by chemical oxidation of pyrrole from acid solutions of H 2 O 2 , K 2 S 2 O 8 , K 2 Cr 2 O 7 , FeCl 3 and Fe 2 (SO 4 ) 3 . Cyclic voltammograms and charge-potential data are obtained for these PPY films in 0.1 M LiClO 4 and 0.1 M Na 2 SO4 solutions. Chemically deposited PPY films are electrochemically active and yield oxidation-reduction peak potentials that are similar to those of PPY films electrochemically synthesized in solutions with the same anions. The shape of the cyclic current-potential curves and the charge-potential responses of the chemically deposited PPY depend on the bath composition. The bath determines the counter anion introduced into the PPY film. The physical appearance and thickness of a film depends on the deposition time, acidity and composition of the electroless plating baths.
Early stages of copper microparticles electrodeposition on polypyrrole film
Composites Communications, 2018
In this work, we studied the electrodeposition of copper (Cu) microparticles on polypyrrole (PPy) films using cyclic voltammetry and chronoamperometry techniques. The initial stages of Cu deposition were investigated by performing current transients. Models based on Scharifker and Hills calculations were established to determine the nucleation and growth type. The results suggest that the deposition of Cu proceeds via an instantaneous nucleation followed by three-dimensional (3D) diffusion-limited growth. The values of the number density of active sites N ∞ and diffusion coefficient D were also determined.
An Electrochemical Study of Bulk and Nanowire Morphologies of Electrodeposited Polypyrrole
ECS Transactions
Pyrrole was electrochemically polymerised onto gold electrodes at a fixed potential of 0.80 V vs. SCE to generate polypyrrole (PPy). Depending on the pH of the solution, PPy, was deposited in either a bulk or nanowire conformation. Electrochemical impedance spectroscopy, EIS, experiments were subsequently carried out on a bare gold electrode, PPy nanowires and bulk PPy of two different film surface areas. The impedance data were analysed using equivalent circuits giving information on the electrochemical properties of the polymers. The influence of different electrolytes on the impedance was also examined.
Electrochimica Acta, 1993
Modified electrodes were obtained by electrodeposition on Pt of polypyrrole (PP) from aqueous solutions. The electrode8 obtained in the absence of cytochrome c were tested by cyclic voltammetry in aqueous solutions containing different supporting electrolytes. The current corresponding to the oxidation and reduction of PP as well as the peak potentials depends, when using salts of the same cation, on the nature of the anion. The difference.8 were interpreted in terms of the anion flux in and out the film and/or its adsorption on the film surface which accompanies the oxidation and the reduction of the PP, respectively. The change of the cation also produces some effect on the electrochemical film behavior.
Anionic responses of electrochemically synthesized polypyrrole films
Talanta, 1992
polypyrrole films with thickness of about 8 pm were prepared on platinum by continuous scanning in O.lM pyrrole and O.lM electrolyte (LiCl, LiBF, or NaBF,). Scan-rates of 10, 20 and 50 mV/sec with scan-times of 30,45 and 60 min were used. The potentiometric response of the films was tested over a range of anions. Films were found to be anion-sensitive but very non-selective. The influence of the doping cation was also investigated.
The electrochemical synthesis of polypyrrole at a copper electrode: corrosion protection properties
Electrochimica Acta, 2002
Pyrrole was successfully electropolymerized at a copper electrode in a near neutral sodium oxalate solution to generate a homogeneous and adherent polypyrrole film. The growth of these films was facilitated by the initial oxidation of the copper electrode in the oxalate solution to generate a copper oxalate pseudo-passive layer. This layer was sufficiently protective to inhibit further dissolution of the copper electrode and sufficiently conductive to enable the electropolymerization of pyrrole at the interface, and the generation of an adherent polypyrrole film. These films remained stable and conducting for periods exceeding eight days and exhibited significant corrosion protection properties in acidified and neutral 0.1 mol dm (3 NaCl solutions even on polarization to high anodic potentials. #