NANOMODIFICATION OF POLYPYRROLE AND POLYANILINE ON HIGHLY ORIENTED PYROLYTIC-GRAPHITE ELECTRODES BY ATOMIC-FORCE MICROSCOPY

This paper describes the first observation of localized electropolymer ization of pyrrole and aniline on highly oriented pyrolytic graphite ( HOPG) substrates under atomic force microscopy (AFM) tip-sample intera ctions. A scanning or oscillating AFM tip, providing the horizontal sc ratching force and the vertical tapping force, is essential as the dri ving force for the surface modification with the conducting polymer. T he significant tip effect on the electropolymerization has been discus sed on the basis of the electropolymerization mechanism. It has been s hown that under the AFM tip interaction, the electropolymerization can be blocked on the bare HOPG substrate or enhanced on the as-polymeriz ed film. The localized electropolymerization in selected surface areas enables the nanomodification of lines, square platforms, or hollows o f polypyrrole (PPY) and polyaniline (PAN) on the substrates. The resul t indicates that AFM can be used as a unique tool for nanofabrication of conducting polymers.