Performance of polyaniline pigmented vinyl acrylic coating on steel in aqueous solutions

Using electrochemical impedance spectroscopy method, the performance of vinyl acrylic coating containing polyaniline on steel in 0.1 N HCl, 3% NaCl and cement extract (pH 13.0) has been evaluated. The resistance of the paint coating in all the media has been found to decrease initially from 10⁸ to 10⁶ Ω cm². On subsequent exposure to the aqueous media, the resistance of the coating has been found to increase steadily. Further, the open circuit potential values have been found to shift in active direction initially and then move in noble direction with longer immersion period due to the passivating effect of polyaniline pigment.