<b>Electrochemical properties and electrochemical impedance spectroscopy of polypyrrole-coated platinum electrodes</b>

Abstract

Polypyrrole (PPy) films of different thickness were characterized by electrochemical impedance spectroscopy (EIS) measurements in acetonitrile and aqueous solutions, containing 0.1 M NaClO4 or sodium dodecylsulfate as the dopant. The PPy films were electrochemically deposited on Pt, and their electrochemical properties studied by cyclic voltammetry. Impedance spectra were obtained at potentials ranging from 0 to 0.8 V/SCE. The EIS data were fitted using two different equivalent electrical circuits (depending on the nature of the dopant). They involve a diffusive capacitance, which increased with the passing charge during electrosynthesis (i.e. film thickness) for ClO4-doped PPy, but was practically unaffected by the film thickness in the case of SDSdoped PPy. Also, a double-layer capacitance was found only in the circuit of ClO4-doped PPy. It increased with the film thickness, and showed a minimum near the open-circuit potential. Finally the charge-transfer resistance (Rct) obtained with SDS is nearly 200-fold higher than that obtained with ClO4in the same solvent (H2O). With the same dopant (ClO4-), Rct is about five times higher in acetonitrile relative to water. All these EIS results of the different types of PPy suggest a relation with the wettability of the polymer.

Electrochemical Characterisation of NiII‐Crown‐Type Polyoxometalate‐Doped Polypyrrole Films for the Catalytic Reduction of Bromate in Water

“…This data has also been calculated by quality of the fit model of EIS Spectrum analyser and presented in Table . This different thickness redox switching behaviour of the conducting polypyrrole film was also observed by M. Fall et al (2006) by characterising the different film thickness of PPY with electrochemical impedance spectroscopy …”

“…The behaviour of different POM‐PPY doped film thickness was also recorded by electrochemical impedance spectroscopy and is shown in Figure b. There is not such a significance difference and linearity change but it was observed the Rct values are increases by increasing the thickness of the film . This data has also been calculated by quality of the fit model of EIS Spectrum analyser and presented in Table .…”

“…Moreover, the impedance data results as the solution resistance (Ri) by electrolyte of solution, charge transfer resistance (Rct) and R L (Zw) complex impedance or Warburg impedance, arises by the diffusion of electroactive species (as it applies mostly for the conducting polymer) for both reduced and oxidised domain of POM +PPY doped film are all calculated by quality of the fit model of EIS Spectrum analyser and presented in Table . Exchange current density i o is also calculated (Table ) by Equation (5) …”

Electrically Conductive Hydrogel Nerve Guidance Conduits for Peripheral Nerve Regeneration

“…Impedance in low frequency regions depends on the capacitance of a material; on the other hand, impedance in high frequency regions depends on the ohmic resistance of the electrode. [ 41,42 ] A significantly low impedance of r(GO/GelMA) at all frequencies appeared to result from better capacitance and electrical conductivity.…”

Transition Metal-Substituted Krebs-Type Polyoxometalate-Doped PEDOT Films

“…It is the resistance by the diffusion of the electroactive species ([BiCo] 10– , [BiFe] 8– , and [BiCu] 8– ) from a modified probe to the analyte or vice versa. The exchange current density, i o , is also calculated (Table ) by employing eq . ,− where R ct represents the charge transfer resistance, i o is the exchange current density, T is the temperature taken as 300 K, and F (96 485 C mol –1 ) is the Faraday constant. Exchange current densities reflect intrinsic rates of electron transfer between an analyte and the modified electrode.…”