INVESTIGADORES
BARBERO Cesar Alfredo
artículos
Título:
Electrochemical and ion exchange properties of polyaniline-poly(vinylsulfonate) composites in aqueous and nonaqueous media
Autor/es:
CESAR A BARBERO; MARIA C. MIRAS; OTTO HAAS; RUEDIGER KOETZ
Revista:
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
Editorial:
ELECTROCHEMICAL SOC INC
Referencias:
Año: 1997 vol. 144 p. 4170 - 4174
ISSN:
0013-4651
Resumen:
A composite of polyaniline and poly(vinylsulfonate) was obtained by
electrochemical polymerization of aniline in a solution
containing poly(vinylsulfonate) ions. The
irreversible retention of the polyelectrolyte was confirmed using
Fourier transform
infrared reflection‐absorption spectroscopy. The
symmetric stretching of the
group is observed at ca.
, in addition to the bands due to
polyaniline. The polyelectrolyte is retained even after extensive
cycling in acidic aqueous
or neutral nonaqueous solutions not containing
polyelectrolyte. The composite film is electroactive in aqueous (pH <
7) and
nonaqueous media. The specific charge in aqueous
media is ca. 84 (±2) Ah/kg, as measured using an
electrochemical quartz crystal microbalance (EQCM) (both redox
processes). The ion exchange
of the modified electrode was studied using probe
beam deflection and EQCM. The charge compensation in aqueous solution
involves
a mixed proton and anion exchange. Three different
regimes are observed at different pH values. At pH below −1 and pH above
2, the dominant process of charge compensation is
proton exchange. At intermediate pH values (between −1 and 2), there is
an increased contribution of anion insertion to the
charge‐compensation process. In nonaqueous media, it seems that cations
are retained inside the film and the charge is
compensated only by anion exchange.