The effect of the isopoly tungstate anion on the composition and conductivity of polypyrrole composite films

Abstract

The polypyrrole composite films were prepared by the electropolymerization of pyrrole from the aqueous solution containing isopoly tungstate (poly-W) and the chloride anion (Cl −) at various ratios. The film formation was traced by electrochemical quartz crystal microbalance, and the tungsten concentrations in the films were measured by the inductively coupled plasma spectroscopy. The electric conductivities of the films were measured by the four-point probe method. In the ratio of poly-W concentration to Cl − concentration, ((poly-W)/Cl −)), higher than 1.26 × 10 −2 in the solution the concentration of tungsten in the films showed a constant value at 51 wt.% and the chloride anion was not included in the film. The conductivities of these films showed the constant value about 40 S cm −1. In the ratio lower than (poly-W)/(Cl −) = 1.26 × 10 −2, the conductivity decreased with the decrease of poly-W concentration and the composite films consisted of two layers; the inner layer initially formed contained larger amount of tungsten than that of the outer layer.