Steel Coated with Cationic Poly (Ethylenimine) (PEI) and Anionic Poly (Vinylsulfate) (PVS) Polyelectrolyte Multilayer Nanofilm with Different Benzotriazole Inhibitor Concentrations

Nano-films consisting of an alternating sequence of positively and negatively charged polyelectrolytes have been prepared by means of the electrostatic layer-by-layer sequential assembly technique on mild steels. The mild steels were pretreated electrochemically to modify the mild steel surface. The modification of the mild steel surface resulted in increasing the adhesion of the obtained nano-films and prevented the corrosion attack during the coating processes. Different concentrations of Benzotriazole inhibitor were encapsulated between cationic and anionic polyelectrolytes nano films. The encapsulation of benzotriazole in the deposited nano-films was verified by U.V visible spectroscopy. The work mainly focuses on the effect of these nano-films of polyelectrolytes with inhibitor and without inhibitors on the corrosion protection. Tafel, corrosion potential, potentiostatic and Econ vs. time experiments were carried out in 0.7M NaCl solution. Weight loss method was used for measuring the corrosion rate of coated and uncoated mild steel substrate. A significant improvement in the corrosion protection was achieved especially in the case of electrochemically modifying the mild steel surface and encapsulating the inhibitors between the polyelectrolytes nano-films