Voltammetric anion recognition by a highly cross-linked polyviologen film

A highly cross-linked polyviologen film was prepared by reductive electropo lymerization of a trifunctional monomer with three 4-cyanopyridinium moieti es. The him was deposited on an ITO-deposited glass electrode at higher cur rent efficiency than in the case of a linear polyviologen from a bifunction al monomer. The resulting polymer film shows a clear electrochromism charac teristic of a viologen redox process. The him exhibits typical redox waves in a monomer-free electrolytic solution containing a smaller electrolyte an ion than the anion used in electropolymerization. On the contrary, the film behaves as electrochemically inactive in a solution containing a larger el ectrolyte anion due to its reduced mobility through the cavity in the cross -linked polymer structure. This anion-controlled redox behavior suggested t hat the cavity size in the cross-linked polymer may be determined by the te mplate effect of the electrolyte anion used in electropolymerization, calle d anion-imprinted electropolymerization. These features can be regarded as a new voltammetric anion recognition of the highly cross-linked polyviologe n film. (C) 1999 Elsevier Science S.A. All rights reserved.