The iron/polyaniline interface and its effect on corrosion protection of iron and cold rolled steel in aqueous and salt environments.

The early stages of interface formation between iron and the emeraldine base form of polyaniline (EB) were investigated using iron atoms sputter-deposited in ultra high vacuum onto emeraldine base films, with X-ray photoelectron spectroscopy (XPS) core level spectra taken after each deposition. Based on the chemical shifts of the core level peaks, iron was determined to donate charge (e(-)) into the emeraldine base film. Depth profiling carried out on the emeraldine base side of EB-coated cold rolled steel (CRS) samples showed that iron diffuses into the polymer film all the way to the outer surface, forming metal-polymer complexes with the emeraldine base. Electrochemical potentiodynamic studies were carried out on CRS and EB-coated CRS coupons in salt solutions demonstrating the corrosion protecting ability of EB coats on steel with a reduction in corrosion current and a shift to more noble potentials for the EB-coated CRS coupons.