Organic/inorganic hybrid waterborne polyurethane coatings with self-healing properties for anticorrosion application

In order to maximize the service life of the coating and steel substrate, an organic-inorganic hybrid waterborne polyurethane (WPU) anti-corrosion coating with self-healing properties was prepared. The structure and surface morphology of the nanofiller polydopamine/graphene oxide/polyaniline (PDA/GO/PANI) containing furan groups (f-PFP) were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy and scanning electron microscopy (SEM). The corrosion protection property was investigated by electrochemical impedance spectroscopy (EIS) in 3.5 wt% sodium chloride solution. The self-healing performance was evaluated by measuring the thermal, mechanical, and anti-corrosion properties before and after self-healing. The results confirmed that under the optimum conditions, with f-PFP accounting for 0.5 % of maleimide-modified WPU (m-WPU), the organic-inorganic hybrid coating with the f-PFP additive had a high corrosion resistance in the long term and excellent self-healing properties. These results were mainly due to the synergistic effect of the barrier effect of GO, passivation mechanism of PANI and reversibility of DA bonds.