The synthesis and corrosion protection mechanisms of PANI/CNT nanocomposite doped with organic phosphoric acid

In this paper, PANI/CNT nanocomposites doped with organic phosphoric acid (PANI/CNT (HEDP)) with a PANI nanospheres adsorbed on the surface of CNT micromorphology were successfully prepared. The redox activity of PANI is extended to neutral effectively after compositing with CNT due to the interfacial pi-pi interaction between PANI and CNT. The resulting PANI/CNT nanocomposite has better dispersity in paint resin, causing a more compact nanocoating than polymeric coating revealed by the porosity measurement. The unique cathode suppression of PANI/CNT (HEDP) can be revealed with PANI/CNT (HCl) nanocomposites (doped by hydrochloric acid) as a control by polarization curve analysis on the scratch nanocoating sample. The results of electrochemical impedance and neutral salt spray test confirm that PANI/CNT (HEDP) nanocomposite has much better corrosion protection than PANI/CNT (HCl) nanocomposite. The corrosion protection mechanisms of PANI/CNT (HEDP) nanocomposite are proved to be the synergistic effect of Nanobarrier effect, Anode protection, Cathode suppression and Inhibitor role.