Influence of electropolymerization temperature on corrosion, morphological and electrical properties of PPy doped with salicylate on iron

In this work, the influence of the electropolymerization temperature on corrosion, morphological and electrical properties of polypyrrole (PPy) film is studied. Polypyrrole is electrochemically synthesized on iron in the presence of sodium salicylate. The X-ray diffraction and scanning electron microscopy are performed in order to study the structure and morphology of electrodeposited PPy. The electroactive surface area, corrosion performance and resistance of the PPy film on iron are also investigated as a function of electropolymerization temperature. The results show that the synthesis temperature significantly affects the properties of the PPy film on iron. It is observed that at 25 °C amorphous PPy is formed, whereas lowering the temperature leads to the formation of a film containing crystallites of salicylic acid. The latter reveals lower corrosion protection and a much higher level of resistance compared to the amorphous one. These characteristics were associated with the presence of insulating salicylic acid crystals in the layer structure.