Electrochemical polymerization of pyrrole on Au(111) in sulphuric acid and sodium hexafluoroaluminate solutions monitored by electrochemical scanning tunneling microscopy

The early stages of electrodeposition of polypyrrole (PPy) on an Au(111) surface are studied using in-situ scanning tunneling microscopy under the electrochemical control of the process. Shape, size, nucleation density and dimensionality of the early growth of the polymer phase was of interest. Electropolymerization took place in aqueous electrolytes containing multicharged anions. The diameter of the smallest detected surface particulates was of the order of a few Å in Na3AlF6 solution and a few tens of Å in pyrrole - H2SO4 solution.