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Conducting poly(aniline-co-o-anisidine) (PAS) films with different ratios of aniline units in the polymer chain were prepared by oxidative polymerization of different molar ratios of aniline and o-anisidine in 1 M HCl using cyclic voltammetry. Due to the much higher reactivity of o-anisidine, the structure and properties of PASs were found to be dominated by the o-anisidine units. The polymerization of poly-o-anisidine and PASs followed zero-order kinetics with respect to formation of the polymer (film thickness) and the autocatalytic polymerization of aniline was completely inhibited. In contrast to polyaniline, a decrease in the polymerization temperature was found to increase the amount of copolymer formed and its redox charge. The presence of aniline units in PASs led to a pronounced increase in the molecular weight and conductivity, and a decrease in the solubility in organic solvents. Repetitive charging/discharging cycles showed that PASs resist degradation more than polyaniline.

The passivation behaviour of e-brass (Cu : Zn = 67: 33) in alkaline solutions was studied using cyclic voltammetry and potentiostatic current transient measurements. The recorded cyclic voltammograms exhibited the main features usually observed for pure copper and zinc, and one additional anodic peak on the reverse potential scan. The height, sharpness and location of the different peaks depended greatly on the alkali concentration and the scan rate. The results show that the formation of Cu20 and Cu(OH)2 films proceed under ohmic resistance control following a dissolution-precipitation mechanism. The effect of F-, C1-and Br-ions on the passivity was also studied. The pitting potential was found to decrease with logarithm of halide ion concentration. The current transients in the absence and presence of halide ions were analysed. In the absence of pitting the current, after a few seconds, was found to increase linearly with the reciprocal of the square root of time while in the presence of pitting it was found to fit the Engell-Stolica equation.

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The passivity of copper in NaOH and borate buffer solutions wntainingcbloride, bromide and fluoride ions was studied by using cyclic voltammetry and potentiostatic current transient measurements. At scan rates 3 20 mVs-*, the addition of halide ions does not nearly affect the cyclic voltammograms in the absence of pitting. But they differ considerably in presence of pitting. The pitting potential was found to depend on the solution pH and decreased linearly with increase of logarithm of halide ion concentration.The current transients in the passivity as well as in the pitting potential regions were analyzed. Before the pitting, i-time curves were rather similar to those obtained in the plain solutions. At times >20 seconds, the current varies linearly with the reciprocal of the square root of time indicating diffusional characteristics of the metal corrosion through the passive layer. In presence of pitting, the pitting current versus time relations fit the Engell-Stolica equation.Die Passivitat von Kupfer in Chlorid-, Bromid-und Fluoridionen enthaltender Natronlauge und Boratpufferlosung wurde mit Hilfe der zyklischen Voltammetrie und der Messung der potentiostatischen Stromtransienten untersucht. Bei Vorschubgeschwindigkeit b 20 mVs-' wird durch die Zugabe der Halogenidionen das zyklische Voltammogramm fast nicht beeinfluRt, sofern keine Lochkorrosion auftritt. Liegt jedoch auch Lochkorrosion vor, so ergeben sich betrachtliche Unterschiede. Das Lochkorrosionspotential ist abhangig vom pH der Losung und nimmt mit zunehmendem Wert des Logarithmus der Halogenidkonzentration linear ab. Die Stromtransienten im Passivitatsbereich und im Bereich des Lochkorrosionspotentials wurden analysiert.Vor Beginn der Lochkorrosion sind die i-t-Kurven weitgehend tihnlich den in halogenidfreien Usungen. Nach mehr als 20s andert sich der Strom linear mit dem reziproken Wert der Quadratwunel aus der Zeit, was ein Indiz fiir die Diffusionsabhangigkeit der Metallkorrosion durch die Passivschicht ist. Wenn Lochkorrosion auftritt, so entspricht der Verlauf der Lochkorrosionsstrodzeit-Kurve der Gleichung von Engell-Stolica.

New conducting polymer films have been prepared on platinum electrodes by anodic polymerization of 1‐naphthol in the presence of methyl naphthyl ether (MNE) in MeCN containing 0.1 M LiClO4. The presence of MNE was found to suppress oligomer formation and significantly affect the physicochemical properties of the polymeric films formed via copolymerization, as confirmed by IR and elemental analysis. In contrast to the autocatalytic polymerization mechanism observed during poly(1‐naphthol) formation, a competitive catalytic‐inhibiting mechanism was found for the copolymer. The copolymer (1:1 and 1:10 1‐naphthol:MNE) showed electrochemical activity similar to that of poly(1‐naphthol). The copolymer films resisted degradation in MeCN effectively and charging–discharging cycles led to doubling of the redox charge after about 20 cycles, while poly(1‐naphthol) films lost 90% of the redox charge under the same conditions. The conductivity of copolymer (1:1) films were 1–2 orders of magnitude lower than that of poly(1‐naphthol). The diffusion coefficients of the charge transfer for the doping–dedoping processes of the copolymer films were slightly lower than for poly(1‐naphthol), but the diffusion coefficients for the redox [Fe(CN)6]3−/4− were comparable for both films. © 2000 Society of Chemical Industry