Formation of a novel electroactive film by electropolymerization of ortho-aminophenol (original) (raw)
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Journal of Electroanalytical Chemistry, 1989
The anodic oxidation of ortho-aminophenol (oAP) in acid aqueous media on different electrode materials, leads to the formation of an electroactive polymer, poly(oAP). Cyclic voltammetric studies allow the inference of a quite complex mechanism for the formation of this film. These studies and the spectroscopic data suggest that the structure of poly( oAP) is mainly a polymer of phenoxazine rings. To confirm these studies the electroactive polymer was also prepared by chemical oxidation of oAP and its properties were compared with those of the electrochemically produced poly( oAP). Moreover, a film was obtained by electrooxidation of the cyclic dimer of oAP, the 3-aminophenoxazone (3APZ). The differences between these films are discussed, leading to the conclusion that the actual monomer in the formation of poly( oAP) is 3APZ. However, the fact that the film obtained from pure 3APZ has an ideal nemstian behavior while the one obtained from oAP does not, gives evidence that side reactions and consequently a "side" polymer make the real structure of poly(oAP) more complex. Then the conditions for obtaining reproducible poly( oAP) modified electrodes are proposed.
Electropolymerization of o-Aminobenzoic Acid and Characterization of the Obtained Polymer Films
Poly(ortho-aminobenzoic acid), as a ring substituted derivative of aniline, has been synthesized electrochemically from acid medium on platinum electrode. The reaction parameters such as current density, hydrochloric acid concentration, monomer concentration, temperature, and reaction duration time were investigated. The kinetic study shows that the orders of polymerization reaction are 1.01, 1.33, and 0.41 with respect to hydrochloric acid concentration, monomer concentration, and current density, respectively. The apparent activation energy (Ea) is found to be 134.8 kJ mol1. The polymer films obtained have been characterized by cyclic voltammetry, X-ray diffraction, elemental analysis, thermogravimetric analysis, scanning electron microscopy, 1H-NMR, and IR spectroscopy. The mechanism of the electrochemical polymerization reaction has been discussed
Preparation of thin polymeric films on electrode surfaces by electropolymerization of o-aminophenol
Macromolecules, 1988
The electro-oxidative polymerization of 2,3-DAN + and 1,8-DAN + in acidic aqueous and acetonitrile solutions was carried out. In both cases, polymeric films were prepared as brown, thin coatings (0.5-5 ~m) on electrode surfaces. The films were electroactive in aqueous solutions and were semiconducting. The formal redox potentials of poly(2,3-DAN) and poly(l,8-DAN) films + were ca.-0.20 and 0.16 V vs. a sodium chloride saturated calomel electrode, respectively, in 0.2 M NaCIO 4 aqueous solution (pH 1.0). The electrochemical and spectroscopic characterization of these films demonstrated that poly(2,3-DAN) is a ladder polymer with phenazine rings as electroactive sites and that the electroactive sites of poly(l,8-DAN) film are different from those of poly(2,3-DAN) film.
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
Polymer International, 1998
The e †ect of temperature on the electrochemical synthesis of poly(oanisidine) (POA) thin Ðlms has been investigated. The POA Ðlms were synthesized electrochemically under cyclic voltammetric conditions in aqueous solutions of at various temperatures between [6¡C and 40¡C. These Ðlms H 2 SO 4 were characterized by cyclic voltammetry (CV), UVÈvisible spectroscopy and scanning electron microscopy (SEM). It has been found that the rate of polymer formation depends on the synthesis temperature and is highest at 15¡C. The optical absorption spectra indicate a major peak at about 800 nm and a shoulder at about 440 nm independent of the synthesis temperature. The peak at about 800 nm corresponds to the presence of the emeraldine salt phase of POA, while the latter may be attributed to the formation of radical cations. The absorbance and width of the peak at about 800 nm is observed to increase at low synthesis temperatures. The POA Ðlm synthesized at 15¡C shows predominant formation of the emeraldine salt phase of POA. The surface morphology as revealed by SEM, is observed to depend on the synthesis temperature, and is caused by di †erent rates of polymer formation at di †erent temperatures. 1998 SCI.
Electropolymerization Kinetics of o-Aminophenol and Characterization of the Obtained Polymer Films
Poly(ortho-aminophenol) has been synthesized electrochemically from a previously deoxygenated acid medium. The initial rate of electropolymerization reaction on platinum electrode is small and the rate law is: Rate = k2 [D]0.50[HCl]1.125[M]1.29. The apparent activation energy (Ea) was found to be 68.63 kJ mol1. The polymer films obtained have been characterized by cyclic voltammetry, X-ray diffraction, elemental analysis, TGA, scanning electron microscopy, 1H NMR, UV–visible, and IR spectroscopy. The mechanism of the electrochemical polymerization reaction has been discussed. J Appl Polym Sci 99: 3093–3109, 2006
Journal of Applied Polymer Science, 2012
Electropolymerization of 2-aminobiphenyl was carried out on glassy carbon, gold, and platinum electrodes, in aqueous-organic solvent mixtures, using a potentiodynamic technique. The choice of organic solvent strongly influences the film formation. In a mixture of 60% acetonitrile and 40% 1.0M HClO 4 , stable films were obtained. The poly(2-aminobiphenyl) films were characterized with cyclic voltammetry, where the electrochemical activity of the formed polymer films was investigated in acidic and neutral aqueous solutions containing perchlorates or in potassium ferrocyanide. The prepared films posses a remarkable stability in acidic aqueous solutions and are also stable in some organic solvents. The stability of the polymer films depends on the pH of the solution, and the mechanism of the polymerization process involves deprotonation and head-to-tail coupling of oxidized monomers with its oligomeric radical cations. The kinetics of the electropolymerization process was investigated by determining the charge consumed during the electropolymerization as a function of time at different concentrations of the electrolyte components. The electropolymerization process follows first-order kinetics with respect to the monomer and negative order with respect to HClO 4. V
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.