Investigation on anticorrosion performance of nano and micro polyaniline in new water-based epoxy coating

In this research, a micro polyaniline (MicroPAni) and a dispersion of nano polyaniline particles (NanoPAni) were used as anticorrosion additive in a new water-based epoxy coating. Both materials were added directly to a new water-based hardener (RIPI-W.B.H.). The resulted mixtures were homogenized and sonicated for size reduction and better particle dispersion. The average particle size of polyaniline in the hardener was determined using dynamic light scattering (DLS). Transmission electron microscopy (TEM) was used to observe the particle size of polyaniline in the final dried film. After applying the coatings on metal surface, anticorrosion performance and adhesion properties of the coatings were compared together with a reference coating using salt spray and cross-cut adhesion tests. The results showed that anticorrosion performance of coating containing NanoPAni was better than the one for coating containing MicroPAni. In addition, investigation on the morphology of metal-coating interface by scanning electron microscopy (SEM) technique in samples containing polyaniline after salt spray test showed stable oxide layer formation on metal surface, which will enhance the corrosion resistance.