G. Schiavon et al., AN ELECTROCHEMICAL QUARTZ-CRYSTAL MICROBALANCE-BASED INVESTIGATION OFTHE PROPERTIES DISPLAYED BY ELECTROACTIVE POLYPYRIDINE FILMS, Analytica chimica acta, 305(1-3), 1995, pp. 212-218
The properties of poly-2,5-pyridine films, deposited on gold electrode
s through a nickel-catalyzed cathodic polymerization route carried out
in acetonitrile, were re-investigated by electrochemical quartz cryst
al microgravimetry in conjunction with cyclic voltammetry and coulomet
ry. Special attention was paid to the ion transport during film reduct
ion and ion binding of the polymer characterized by both electroactive
and coordinative properties. The suitability of the electrochemical q
uartz crystal microbalance for the study of chemically modified electr
ode surfaces results in reliable information pointing out that polymer
ic chains in the framework are characterized by the presence of bipyri
dyl moieties grafted upon one another by coordinating nickel(II) ions
whose coordination shell was identified. Moreover, the nickel-doped po
lymer turned out to undergo two cathodic processes both leading to the
polymer changing from the insulating to the conductive state. The for
mer is due to the reduction of coordinated nickel ions and is accompan
ied by the release of the counter anions originally present, while the
uptake of cations from the supporting electrolyte is accompanied with
reduction by the injection of electrons into the polymer backbone. Th
e program developed for the simultaneous acquisition of experimental d
ata and their processing is described.