Smart self-healing coating based on the highly dispersed silica/carbon nanotube nanomaterial for corrosion protection of steel

Abstract

The poor dispersion of carbon nanotubes (CNTs) limits their practical enhancement in polymer matrix due to strong Van der Waals force among them and their high aspect ratio. Here, a highly dispersed silica/carbon nanotube (HAC) nanomaterial was prepared, which effectively solved the agglomeration problem of CNTs-based materials. More importantly, X-ray photoelectron spectroscopy (XPS), Thermogravimetric analysis (TG) and UV–vis spectra results confirm that HAC nanomaterials can achieve the loading and release of corrosion inhibitors. Basing on these, we developed a smart self-healing coating system (HACB/EP) to further improve the corrosion resistance of the coating. Electrochemical impedance spectroscopy (EIS) investigation shows that HACB/EP still has the highest low-frequency impedance value compared with other coatings after 30 d of immersion, and the electrochemical self-healing efficiency (ηes) of HACB/EP with an artificial defect (De-HACB/EP) turns into positive values at the second (24–48 h) and third (48–72 h) stage. In general, the enhanced corrosion protection and excellent self-healing performance of HACB/EP will greatly promote the development of smart anticorrosion coatings.