Conductivity of polypyrrole films doped with aromatic sulphonate derivatives

The conductivity of polypyrrole films doped with various kinds of aromatic sulphonate derivatives has been studied. The conductivity of polypyrrole films could be varied by more than an order of magnitude by the current density chosen in the film preparation, and the highest conductivity was achieved at moderate current densities such as 0.2 mA cm–2. The film conductivity was also influenced greatly by the number of sulphonate groups of a dopant molecule in such a manner that an increase in the number caused the conductivity to decrease. This effect was especially noticeable for polypyrrole films prepared at relatively low current densities such as 0.005 mA cm–2.