AFM study of the adsorption of pyrrole and formation of the polypyrrole film on gold surface

Pyrrole (Py) adsorption and following electropolymerisation processes onto partially atomically flat Au (111) surfaces from aqueous solution of 0.1 M Py plus 0.1 M LiClO4 have been investigated by non-contact atomic force microscopy. The adsorbed layers were examined, firstly in-situ, in solution of Py plus electrolyte and in pure electrolyte, and secondly ex-situ, in dried condition in air atmosphere. AFM images show clearly that in all cases the surface of the Au (111) electrode is covered with polymolecular adsorbed layer of Py. Electropolymerisation of the adsorbed Py layer causes some typical changes in the nanostructure of the layer: relatively larger nuclei disappear and honeycomb-like structures and ensembles of the middle size nuclei appear.