Effect of non-electroactive additives on the early stage pyrrole electropolymerization on indium tin oxide electrodes

• Early-stage polymerization polypyrrole particles on indium tin oxide (ITO).
• Anionic additives promote pyrrole oxidation and polypyrrole film growth on ITO.
• Cationic polyelectrolyte promotes adhesion between ITO and polypyrrole film.
• Non-electroactive additives strongly influence polypyrrole nucleation on ITO.

The use of non-electroactive additives during electrodeposition of conducting polymers has long been used to modify the properties of deposited films. These additives can improve the adhesion, and not only change the morphology and deposition rate but also modify the chemical composition of the electrodeposited polymer. Several compounds have been used to modify deposition of polypyrrole; however, there is no systematic study of these compounds. In this work, we comparatively studied several water soluble chemical compounds, a cationic polymer, an anionic polymer, a cationic surfactant, and an anionic surfactant during potentiostatic electrodeposition of polypyrrole. In order to study the effect of these compounds on the interface, where the electrochemical polymerization takes place, we used electrochemical impedance spectroscopy. The morphology during the initial stage of growth was studied by atomic force microscopy, whereas the resulting polypyrrole films were observed by scanning electron microscopy.