Anticorrosive polystyrene coatings modified with tannic acid on zinc and steel substrates

Polystyrene (PS) polymer layers were prepared by the sol-gel method and studied as anticorrosive barrier layers on carbon steel and zinc substrates. To increase the corrosion resistance of the coatings, two different approaches were considered: (i) the use of mesoporous silica-nanocontainers impregnated with a corrosion inhibitor (tannic acid) introduced into the polystyrene matrix and (ii) direct impregnation of polystyrene coatings with the same corrosion inhibitor. The impregnated nanocontainers were characterized by transmission electron microscopy. The thickness and the adhesion of the coatings were measured, and their corrosion behavior was investigated by electrochemical impedance spectroscopy. Results showed that the used inhibitor slightly decreased adhesion, but significantly increased the corrosion resistance of the coatings. The direct introduction of tannic acid into the polymer matrix offers higher corrosion resistance than in the case of polystyrene coatings doped with impregnated silica nanocontainers.