Electrochemical quartz crystal microbalance study of the influence of the solution composition on the behaviour of poly(aniline) electrodes

S. Pruneanu, E. Csahók, V. Kertész, G. Inzelt

Research output: Contribution to journalArticle

80 Citations (Scopus)

Abstract

Cyclic and potentiostatic electrochemical quartz crystal microbalance measurements are reported for poly(aniline) deposited on Pt electrodes and immersed in aqueous solutions of HClO4, 4-toluenesulfonic acid and 5-sulfosalicylic acid. The effect of solution composition on the mass changes occurring simultaneously with electrochemical transformations of the polymer was investigated. The results indicate that the pH and potential-dependent relative contribution of anions and cations to the overall ion exchange process is in connection with the degree of protonation of the reduced, partially and fully oxidised forms of the poly(aniline). The small mass change at lower potentials can be rationalised in terms of a model in which it is assumed that the expulsion of protons at the beginning of the first oxidation step and the incorporation of anions at a later stage of oxidation is basically determined by thermodynamics and not the kinetics of the system. Kinetic complications also arise for several reasons such as slow diffusion of ions and solvent molecules and relaxation of the polymer network. The actual film morphology depends on the nature of the solution used. It is proved that the pore size exclusion effect in the case of larger anions does not exist as thought previously, inasmuch as the originally compact structure formed in perchlorate solution can be transformed to a more open and swollen one under continuous cycling in the solution containing electrolyte of large ions.

Original languageEnglish
Pages (from-to)2305-2323
Number of pages19
JournalElectrochimica Acta
Volume43
Issue number16-17
DOIs
Publication statusPublished - May 29 1998

Keywords

  • 4-toluenesulfonic acid
  • 5-sulfosalicylic acid
  • Electrochemical quartz crystal microbalance
  • Ion transport
  • Perchloric acid
  • Poly(aniline)
  • Swelling

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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