Electrodeposition of Adherent Polyaniline-Polypyrrole Composite Coatings on Low Carbon Steel

Uniform and adherent polyaniline-polypyrrole composite coatings were electrochemically polymerized on low carbon steel under aqueous conditions. The structure of the coatings was analyzed as a function of electrochemical deposition parameters (molar feed ratio of monomers and reaction time). X-ray photoelectron spectroscopy (XPS) was used to study the chemical composition of the coatings and also the amount of dopants (oxalate ions) incorporated into the polymeric coatings. The morphology of the coatings was studied using scanning electron microscopy (SEM). The adhesion strength of the coatings was measured using simple lap joint tests. The composite coatings formed by an equimolar feed of the monomers were much more adherent than the homopolymeric coatings.