INVESTIGADORES
MOLINA fernando Victor
artículos
Título:
Quasi-equilibrium volume changes of polyaniline films upon redox switching. formal potential distribution and configurational modeling
Autor/es:
LEONARDO LIZARRAGA,; E. M. ANDRADE; F. V. MOLINA
Revista:
JOURNAL OF PHYSICAL CHEMISTRY B
Editorial:
ACS
Referencias:
Lugar: Washington; Año: 2005 vol. 109 p. 18815 - 18821
ISSN:
1089-5647
Resumen:
The quasi
equilibrium electrochemomechanical behavior of relatively thick PANI films in
sulfuric acid is investigated through experimental measurements and theoretical
modeling. The leucoemeraldine (LE)-emeraldine (EM) conversion, or redox
switching, is studied. The dependence of film volume and electrochemical charge
is determined as a function of applied potential. It is observed that the film
volume follows the charge, showing an expansion during the second half of the
LE-EM oxidation. The model postulates the existence of a stable intermediate,
protoemeraldine (PE), with a formal potential distribution for the PE-EM
reaction. The volume change is modeled statistically considering contributions
from mixing, polymer deformation and electrostatic charge. The model shows very
good agreement with the experiments indicating that, in the conditions studied,
the deformation contribution dominates the volume changes, due to the
conformational modifications undergone by the polymer in the PE-EM oxidation.