Electropolymerization features of o-phenylenediamine on carbon electrode with developed surface (original) (raw)
Related papers
Journal of Applied Polymer Science
Electropolymerization of O-phenylenedi-amine (o-PD) on Pt-electrode from a deoxygenated aqueous acid medium was carried out using cyclic voltammetry technique. The kinetic parameters were calculated by means of electrochemical data. The experimentally obtained kinetic equation was R P , E ¼ k E [monomer] 1.19 [acid] 1.23 [electro-lyte] 0.87 from the value of the anodic current density using cyclic voltammetry technique. The apparent activation energy (E a) is found to be 28.34 kJ mol À1 . The polymer films obtained have been characterized by X-ray diffraction, elemental analysis, scanning electron microscopy, 1 H-NMR, 13 C-NMR, UV-visible, and IR spectroscopy. The mechanism of the electrochemical polymerization reaction has been dis-cussed. TGA is used to confirm the proposed structure and determination of the number of water molecules in the pol-ymeric chain unit. V
Electropolymerization of p-phenylenediamine (pPD) on Pt-electrode from a deoxygenated aqueous acid medium was carried out using cyclic voltammetry technique. The kinetic parameters were calculated by means of electrochemical data. The experimentally obtained kinetic equation was RP,E ¼ kE [monomer]1.23 [acid] 1.24 [electrolyte]0.94 from the value of the anodic current density. The apparent activation energy (Ea) is found to be 65.1 kJ mol 1. The obtained polymer films have been characterized by X-ray diffraction, elemental analysis, scanning electron microscopy, UV–vis, and IR spectroscopy. The conductivity of the polymer pellets is 6.3 10 7 S cm 1. The mechanism of the electrochemical polymerization reaction has been discussed. TGA is used to confirm the proposed structure and determination of the number of water molecules in the polymeric chain unit.
Electrochemical copolymerization of o-toluidine and o-phenylenediamine
Journal of Electroanalytical Chemistry, 2006
Electroactive copolymers of o-toluidine (OT) and o-phenylenediamine (OPD) were electrosynthesized in aqueous sulfuric acid. Cyclic voltammetry was used both for the electrochemical synthesis and characterization of the copolymers deposited on a gold electrode. The voltammograms exhibited different behavior for different concentrations of OPD in the feed. At optimum conditions the rate of copolymerization was found to be between the rates of homopolymerizations. The resulting poly(OPD-coOT) shows an extended useful potential range of the redox activity as compared to the corresponding homopolymers. The effect of scan rate and pH on the electrochemical activity was studied. The copolymer was electrochemically active even at pH 9.0. In situ conductivity measurements further support the formation of a copolymer because the copolymers have a potential region of maximum conductivity completely different from that of POT. However, conductivities of the copolymers were lower by 2-2.7 orders of magnitude than of POT.
Journal of Electroanalytical Chemistry, 2013
The physico-chemical characteristics of thin poly-(ortho-phenylenediamine) (PPD) films, obtained by electrochemical oxidation of the relevant monomer, are investigated using electrochemical, morphological and spectroscopic techniques. In particular, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques are used to collect information concerning the redox, conductivity and double layer capacitance properties of the PPD film. AFM imaging and Raman spectroscopy results are exploited to characterize the film structure. In this respect, Raman spectra of two possible PPD oligomers are calculated at the B3LYP/6-311G ÃÃ level of the theory.
An effect of carbonization on the electrorheology of poly(p-phenylenediamine)
Carbon, 2013
Particles of poly(p-phenylenediamine) were synthesized by the oxidation of pphenylenediamine with ammonium peroxydisulfate at two oxidation levels. They were carbonized at 200-800 °C in inert atmosphere and subsequently tested in electrorheological (ER) suspensions. Scanning electron microscopy, Raman spectroscopy and thermogravimetric analysis were used to characterize an influence of the carbonization on the molecular structure and particles size and shape.
International Journal of Electrochemical Science, 2012
Poly(ortho-Phenylenediamine) was deposited as a thin film by electrochemical impedance spectroscopy (EIS) and compared to cyclic voltammetry (CV) on Teflon insulated Platinum–Iridium (Pt) disk microelectrode (125 μm diameter) in 300 mM phosphate buffer solution (pH 7.2). This study focuses on the electropolymerization process and electrical properties of PoPD-modified microelectrodes, using EIS technique. The estimated thickness of the PoPD film was 31 nm with conductivity of 1.1 x 10 −5 Scm −1 . The initial impedance plot shows a semicircle which characterized the charge-transfer resistance at the microelectrode/polymer interface at higher frequency and a diffusion process at lower frequency. Impedance data were fitted to the Randles and a modified Randles circuit models with χ 2 = 0.12 and χ 2 = 0.06 respectively. The capacitive behavior (phase angle = 83°) of the bare Pt microelectrode was transformed to a resistive behavior (phase angle = 13°) after the formation of PoPD layer a...
Electrochemical copolymerization of m-toluidine and o-phenylenediamine
Electrochimica Acta, 2006
Electroactive copolymers of m-toluidine (MT) and o-phenylenediamine (OPD) were prepared electrochemically in aqueous sulfuric acid by potential cycling and characterized with cyclic voltametry, in situ conductivity measurements and FT-IR spectroscopy. The voltammograms of the copolymers exhibit different behavior for different concentrations of OPD in the comonomer feed. At optimum conditions the resulting poly(OPDco-MT) shows an extended useful potential range of the redox activity as compared to the corresponding homopolymers. The effect of scan rate and pH on the electrochemical activity was studied. The copolymer was electrochemically active even at pH 8.0. The stability of the copolymer film was also tested. The copolymer has a potential region of maximum conductivity different from that of PMT and POPD. The conductivity of the copolymer is between the conductivity of the homopolymers. The vibrational bands at 3122/3450 and 2922/875 cm −1 in the FT-IR spectra of the copolymer indicate the presence of both OPD and MT units, respectively, in the copolymer backbone.
Electrochemistry Communications, 2008
In attempts to improve the permselective properties of poly(o-phenylenediamine), PoPD, for biosensor applications, its electrosynthesis was carried out in the presence and absence of a variety of background electrolytes. Surprisingly, not only was electropolymerization efficient when no charge carriers were added to the monomer solution, the selectivity of the PoPD generated under this condition was superior to other published forms. Interpretation of these findings in terms of ion entrapment also supports the hypothesis that self-blocking by biosensor interference species present in solution is involved in determining PoPD permeability, which increases selectivity in bio-monitoring applications.
Electrochemistry, 2013
Poly(1-amino-9,10-anthraquinone-coo -phenylenediamine) (P1AAQ-co-POPD) was synthesized by electrochemical methods on stainless steel electrodes (SS) using equal monomer concentration in acetonitrile/acidified water mixture as solvent. Electrochemical characterization allows, among others, determining the characteristic redox couple potential of the quinone group, which is one of the advantages of having achieved the copolymerization. FT-Raman, ATR and UV-Vis characterization confirms the formation of the copolymer, particularly, by the occurrence of a novel signal ascribed to a new C-N type bond. Besides, the conductivity of the deposits was determined, which enabled the conducting properties of the products to be verified. The topographical and morphological characterization accomplished by atomic force (AFM) and transmission electron (TEM) microscopy showed how the inclusion of o-phenylenediamine (OPD) increases the homogeneity of the copolymer, which in turn enables designing likely applications of the electrode modified with this novel polymeric material.
Electro-oxidation of o-phenylenediamine at platinum electrodes in acetonitrile solutions
Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1979
The study of o-phenylenediamine electro-oxidation at platinum electrodes in acetonitrile solutions under different experimental conditions is presented. Cyclic voltammograms show 4 oxidation peaks, which are assigned to o-phenylenediamine, o,o'-diamineazobenzene and protonated o-phenylenediamine anodic oxidation. An additional prepeak system is apparent at potentials less anodic than the first peak in successive scans. This prepeak system evidences the presence of two redox systems diphenylamine and H ÷, derived from the initial oxidation product o-phenylenediamine cation radical. The effect of base and acid addition is also studied, o,o'-Diamineazobenzene was identified as one of the principal soluble products in preparative scale electrolysis and a general mechanism for o-phenylenediamine oxidation is proposed.