Phytic acid-doped polypyrrole/graphene oxide nanofillers for the preparation of self-healing anticorrosion coatings with the synergistic physical barrier, passivation and chelating effect

Abstract

The corrosion protection of organic coatings for metal substrates is generally limited because of the unavoidable coating micropores and cracks, even the coating anticorrosion function will lose when it is damaged. Although the addition of nanofillers into the organic coating matrix can effectively address the above issues, it is challenging to facilely and wholesale construct surface-modified nanofillers with synergistic anticorrosion ability of physical barrier, passivation and chelating effect. In this study, we develop a simple one-pot approach for preparing polypyrrole (PPy) modified graphene oxide (GO) nanofillers with the doping of phytic acid (Ph) (namely GO-PPy@Ph nanoparticles) and then incorporating them into epoxy resin (EP) coating system to form the anticorrosion nanocomposite coatings. The research results display that the GO-PPy@Ph nanoparticles can uniformly disperse in the EP coatings to improve their anti-penetrant ability against corrosive media. And the introduction of GO-PPy@Ph nanoparticles effectively enhances the coating adhesion strength and mechanical performance. Moreover, the anticorrosion tests show that the impedance modulus at 0.01 Hz of GO-PPy@Ph coating after 60-day immersion in 3.5 wt% NaCl solution remains at about 1010 Ω cm2. The dramatical anticorrosive performance of the GO-PPy@Ph coating with self-healing performance is attributed to the synergistic protection of impermeable GO-PPy@Ph nanosheets, passivation function of PPy and metal chelation effect of Ph. This study provides an effective and universal avenue to construct multifunctional nanofillers with the synergistic anticorrosion of high physical barrier, passivation and metal chelating effects for developing anticorrosive nanocomposite coatings with high performances, which have highly attractive potential in the commercialization applications of metal corrosion protection.