HIGHLY ANISOTROPIC ELECTRICALLY CONDUCTING FILMS BASED ON POLYPYRROLE

Electrically conducting films of polypyrrole prepared using a pulsed electrochemical potential exhibit a marked increase in molecular anisotropy, electrical conductivity and surface smoothness, as compared to equivalent films synthesized under constant potential conditions. These enhancements are only observed when the polypyrrole films are prepared from aqueous electrolytes containing toluene sulphonate as the dopant or counterion. X-ray scattering patterns show that the polypyrrole films are highly anisotropic with the planes of the pyrrole rings lying preferentially parallel to the electrode surface. The pulse lengths and voltages are most important to preparing enhanced films and appear to indicate that these improved films grow as a consequence of an increase in the number of equivalent growth sites.