Microelectrode studies of fast switching in polyaniline films

Kalaji, M.; Peter, Laurence M.; Abrantes, L.M.; Mesquita, José Carlos

doi:10.1016/0022-0728(89)87051-2

Cited by 133 publications

(18 citation statements)

References 11 publications

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“…Further, it is not surprising that during repetitive potential cycling the consecutively appearing oxidation peaks of PANI are very sensitive to scan rate and/or preconditioning (holding) at the reduction potential (À 0.1 V). The above characteristic of the PANI microdeposits is in agreement with the earlier observations made for the PANI films of various sizes [34,35]. The complexity of the oxidation process was also previously demonstrated during potential step (chronoamperometric) experiments [35].…”

Section: Dynamics Of Charge Transportsupporting

confidence: 85%

“…The above characteristic of the PANI microdeposits is in agreement with the earlier observations made for the PANI films of various sizes [34,35]. The complexity of the oxidation process was also previously demonstrated during potential step (chronoamperometric) experiments [35]. Consequently, only reduction steps that can be described in terms of the well-defined Cottrell-type responses [36] have been considered in the further work.…”

Section: Dynamics Of Charge Transportsupporting

confidence: 80%

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Microdimensional Polyaniline: Fabrication and Characterization of Dynamics of Charge Propagation at Microdisk Electrodes

Caban¹,

Kulesza²,

Stojek³

et al. 2004

Electroanalysis

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We describe fabrication of microdimensional polyanilne films in a controlled manner by voltammetric potential cycling or controlled potential electrolysis on platinum microdisk electrodes. The film grows in a form of hemispherical microdeposits, and its size largely exceeds the size of a Pt microdisk. Consequently, the film covers both the Pt substrate as well as the surrounding glass seal. Since the adhering polyaniline layer is conducting, the latter situation may lead to an increase in the effective electrode surface area. The lateral growth of polyaniline films outside the microdisk has also been demonstrated by performing diagnostic voltammetric experiments with use of a double microdisk set-up in which independent polarization of each disk is feasible. Microelectrode-based chronocoulometry, that involves an uncomplicated well-defined reduction potential step starting from the emeraldine (conducting) form and ending at leucoemeraldine (nonconducting) form, yields (upon application of a sufficiently short pulse) a welldefined linear response of charge versus square root of time that is consistent with the linear effective diffusion as the predominant charge propagation mechanism. When describing the system kinetics in terms of the effective (apparent) diffusion coefficient, we expect this parameter to be on the level of 10 À8 cm 2 s À1 or lower. The relative changes in dynamics of charge transport are discussed with respect to the polyaniline film loading, the size of microdisk electrode, expansion of the active electrode area, and the choice of electrolyte (strong acid) anion. The results are consistent with the view that when Pt microelectrode is modified with PANI deposit exceeding the size of the microdisk substrate, it behaves in a way as if its surface area is effectively much larger than the geometric area of Pt microdisk.

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Section: Dynamics Of Charge Transportsupporting

confidence: 85%

Section: Dynamics Of Charge Transportsupporting

confidence: 80%

Microdimensional Polyaniline: Fabrication and Characterization of Dynamics of Charge Propagation at Microdisk Electrodes

Caban¹,

Kulesza²,

Stojek³

et al. 2004

Electroanalysis

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“…Therefore, the general theoretical description of transient currents following the potential step application for electrodes coated by a conducting polymer is still a challenge and is a limitation for potential analytical applications. It was found that the time dependences of the charge/discharge current often could not be described by simple Cottrell equation related to a linear diffusion [21,22] and current maxima just after potential step application are sometimes observed [20,23,24]. Aoki [25 ±27] described the non-monotonous current change by limitations in charge transfer rate.…”

Section: The Role Of the Time Scale Of The Measurement For The Amperomentioning

confidence: 99%

Amperometric Ion Sensing Using Polypyrrole Membranes

2003

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Oxidation/reduction of conducting polymers, coupled with ion exchange between the polymer and electrolyte solution can be utilized for amperometric ion sensing. Electrochemically deposited ™model∫ polypyrrole membranes doped by chloride (PPyCl) and hexacyanoferrate (PPyFeCN) anions were studied from the point of view of their advantages and limits for amperometric determination of electroinactive anions and cations, respectively. Monotonous dependences of the current on electrolyte concentration were obtained for short reading times after potential step application (in the range of ms). The experimental conditions were optimized to obtain linear dependences: log (current) vs. log (KCl concentration) within the range 10 À6 À 1 M. The advantages of the amperometric method over the potentiometric one are highlighted: much lower effect of redox and pH interferences, wider concentration range, elimination of long conditioning procedure.

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“…Charge transport studies of polymer modified ultramicroelec- trodes have recently appeared (36)(37)(38)(39). Conducting polyaniline films have been characterized with cyclic voltammetry and fast scan rate cyclic voltammetry.…”

Section: Resultsmentioning

confidence: 99%