Abstract: Polyaniline doped with an organic phosphate(PANI-OP) was blended with water-borne epoxy resin and used as an anti-corrosion material. The long-term anti-corrosion behavior of the material was investigated. Transmission electron microscopy showed that the PANI-OP powder was uniformly dispersed in the waterborne epoxy resin when the PANI content was below 1%. The diameter of the particle decreased to ca. 50~100 nm when the PANI content was 0.1%. Electrochemical impedance spectroscopy and the changes in open circuit potential indicated that the presence of polyaniline coating significantly improved the anti-corrosion effect. X-rays photoelectron spectra showed that a dense passive film of iron oxide(FeO and Fe2O3) on the surface was accounted for the anti-corrosion; in the meanwhile, the presence of P indicated that the dopant ion was also involved in the corrosion protection process.

Key words: polyaniline, waterborne epoxy resin, mild steel, Anti-corrosion