In situ atomic force microscopy investigation of copper behaviour and polypyrrole deposition from salicylate medium

The morphological modifications accompanying the electrochemical behaviour of copper in aqueous salicylate solution, have been investigated by in situ atomic force microscopy (AFM), with the purpose of elucidating the role of salicylate ions during polypyrrole electrodeposition onto this oxidisable metal.The surface changes revealed by in situ AFM images, are in agreement with previous attributed electrochemical processes, namely the formation of a non-uniform passivating layer, which does not completely block the copper surface. The presence of such layer prevents a strong anodic copper dissolution without hinder the pyrrrole oxidation. Pyrrole electropolymerization process has been also followed in real-time by AFM, and occurs through the formation of a first polymer layer, which follows the initial copper surfaces irregularities and is characterized by polypyrrole round nodules of different sizes, whereas for thick polymer films the influence of substrate defects is not detected.