Extent of incorporation of hydrolysis products in polyaniline films deposited by cyclic potential sweep

Cui, C. Q.; Ong, L. H.; Tan, T.C.; Lee, Jim Y.

doi:10.1016/0013-4686(93)80076-c

Cited by 72 publications

(35 citation statements)

References 27 publications

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“…1b, consists of an intertwined network of fibres, each with a diameter of 0.6 Am. This agrees well with the morphology of polyaniline deposited at platinum [20]. These SEM analyses show that the polymers formed on the iron surface are homogenous and free from any defects that may limit the corrosion protection properties of the coatings.…”

Section: Deposition Of Polyaniline At Ironsupporting

confidence: 84%

Polyaniline-coated iron: studies on the dissolution and electrochemical activity as a function of pH

Fenelon

Breslin

2005

Surface and Coatings Technology

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Polyaniline coatings were electrodeposited from an oxalic acid solution onto iron and their electrochemical activity and corrosion protection properties studied as a function of pH. It was found that the coating (emeraldine salt) had a limited effect on the corrosion protection of iron in acidic solutions. However, in an alkaline borate solution, where the conducting polyaniline was converted to the emeraldine base, the coating had a clear beneficial effect on the local breakdown of iron by chloride anions; much higher pitting potentials were recorded following a 2 h immersion period for the polyaniline-coated substrate relative to the uncoated electrode. Relatively small anions, such as acetates, nitrates and borates, were transported readily across the polymer interface. However, the emeraldine base inhibited the transport of the much larger ethylenediamine tetraacetate (EDTA) species to the iron interface, preventing complexation of the iron by EDTA. D

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Section: Deposition Of Polyaniline At Ironsupporting

confidence: 84%

Polyaniline-coated iron: studies on the dissolution and electrochemical activity as a function of pH

Fenelon

Breslin

2005

Surface and Coatings Technology

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“…These data are similar to those reported by Duić et al [15] who suggest that under acidic conditions two pairs of 'middle peaks' are observed. The peaks at the higher potential of 0.54 V/SCE have also been associated with the formation of soluble benzoquinone, a degradation product of polyaniline [12][13][14][15][16]. The extent of film degradation with continued cycling up to 1.3 V/SCE increases; the peak currents associated with the 'middle peaks' at 0.45 and 0.54 V/SCE increase, while the peak currents corresponding to the leucoemeraldine to emeraldine transition and the emeraldine to pernigraniline transition decrease, as depicted in the plot.…”

Section: Influence Of Cycling Conditions On the Formation Of Polyanilinementioning

confidence: 99%

“…On repetitive cycling of the potential, a progressive increase in the height of this peak is seen, while the reactivation and dissolution peaks (B and A) are no longer evident. This is indicative of the build-up of surface bound electroactive material [14,17]. This process of polyaniline deposition at the corrosion susceptible iron surface from oxalic acid has been discussed by many authors [4,5,18], but generally the mechanism proposed by Mengoli and Musiani [18] is adopted, where the electrode becomes passivated by an oxalate/oxide layer on polarization in the oxalate solution.…”

Section: Influence Of Cycling Conditions On the Formation Of Polyanilinementioning

confidence: 99%

“…Stilwell and Park [13] performed spectrophotometric experiments on oxidized polyaniline and identified benzoquinone as the major soluble degradation product, formed as a consequence of hydrolysis reactions. Cui et al [14] report the presence of hydrolysis products in polyaniline films, which inhibit the fibrilious growth of polyaniline and gives rise to a powdery film morphology. Duić et al [15] suggest that in acidic conditions two pairs of middle peaks are observed in the cyclic voltammograms which originate from the hydrolysis of aminodiphenylamine, a dimer intermediate of polymer growth.…”

Section: Introductionmentioning

confidence: 99%

“…However, it is well know that the application of high anodic potentials, above 0.7 V/SCE in the electrochemical synthesis of polyaniline at inert substrates gives rise to degradation of the polymer [12][13][14][15][16]. For example, Kobayashi et al [12] have observed the degradation of polyaniline films at potentials greater than 0.7 V/SCE and have attributed a pair of redox waves close to 0.5 V/SCE in the voltammetric response of the polymer to a benzoquinone/hydroquinone couple.…”

Section: Introductionmentioning

confidence: 99%

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An investigation into the degradation of polyaniline films grown on iron from oxalic acid

Fenelon

Breslin

2004

Synthetic Metals

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The electrosynthesis of polyaniline at iron from an oxalic acid solution and at platinum from a sulphuric acid solution was compared with a view to determining the extent of film degradation during formation of polyaniline at iron. It was found that polyaniline grown from oxalic acid is less susceptible to degradation, due to the shielding effect of the oxalate counter anions. The benzoquinone/hydroquinone redox couple was detected for polyaniline films formed on platinum and cycled to 1.3 V/SCE, however, this redox species was not detected during the electropolymerization of aniline at iron polarized to potentials of 1.5 V/SCE.

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Electrochemical polymerization of aniline on carbon fibers in aqueous toluene sulfonate solution

Iroh

Rajagopalan

2000

J. Appl. Polym. Sci.

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Polyaniline has been successfully formed by aqueous electrochemical polymerization on carbon fibers. The coatings were formed under potentiostatic conditions with toluene-4-sulphonic acid sodium salt as the electrolyte. The effect of monomer concentration, electrolyte concentration, and the applied potential on the rate of polymerization were studied. The amount of polyaniline coatings formed on carbon fibers increased with increased aniline and electrolyte concentration. Increasing the applied potential also increased the weight of coatings formed on the fibers. The presence of positive y-intercept in the weight gain plots are attributed to the adsorption of the electrolyte on the fibers before electropolymerization. The effect of the electrochemical parameters on the degradation of the polymer has been analyzed using infrared spectroscopy.

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Extent of incorporation of hydrolysis products in polyaniline films deposited by cyclic potential sweep

Cited by 72 publications

References 27 publications

Polyaniline-coated iron: studies on the dissolution and electrochemical activity as a function of pH

Polyaniline-coated iron: studies on the dissolution and electrochemical activity as a function of pH

An investigation into the degradation of polyaniline films grown on iron from oxalic acid

Electrochemical polymerization of aniline on carbon fibers in aqueous toluene sulfonate solution

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