INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Photophysics of polyaniline: sequence-length distribution dependence of photoluminescence quenching as studied by fluorescence measurements and Monte Carlo simulations
Autor/es:
P. S. ANTONEL; E. VÖLKER; F. V. MOLINA
Revista:
POLYMER
Editorial:
ELSEVIER SCI LTD
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 53 p. 2619 - 2627
ISSN:
0032-3861
Resumen:
The dependence of the fluorescence quenching of electropolymerized poly(aniline-co-m-chloroaniline)
with polymer composition has been investigated. Fluorescence emission
in polyaniline is quenched when the polymer is oxidized (brought to
emeraldine state); the copolymers exhibit decreasing quenching as
chloroaniline contents increases. Quenching shows a strong decrease in
the presence of 0.1 % m-chloroaniline monomers in the feed. The
presence of dichloroaniline units in the copolymer was confirmed by XPS
measurements and a terpolymerization reaction scheme was developed,
obtaining the kinetic parameters. By Monte Carlo simulation the
sequence length distributions for different compositions were obtained
and compared; it was found that quenching, for low aniline contents,
requires aniline sequences of at least three units. The strong decrease
in quenching at low m-chloroaniline contents is attributed to a
double effect: breaking of conjugation in the emeraldine form by the
presence of the chlorinated unit, and a disruption of the close chain
packing in the crystalline domains, preventing state delocalization and
thus efficient quenching.