Microstructural studies on polypyrrole

Abstract

Scanning tunnelling microscopy has been used in an attempt to determine the surface roughness of polypyrrole films, prepared by electrodeposition on platinum electrodes. Films of nominal thickness 0.7 and 15 µm were used and compared with bare platinum surfaces using both scanning tunnelling microscopy and conventional scanning electron microscopy. The surface area for the thicker polypyrrole films was found to be ca. 2.5 times that of the underlying platinum surface. This should be contrasted with our previous, much higher, estimate of this parameter (40) from electrochemical measurements (J. Phys. D, 20, 1411). This discrepancy is discussed in terms of the accessibility of internal spaces to electrochemically reactive species.