Anticorrosive durability of zinc-based waterborne coatings enhanced by highly dispersed and conductive polyaniline/graphene oxide composite

We developed a novel environment-friendly waterborne zinc-based coating (ZWC) with good corrosion resistance to reduce the environmental hazards caused by solvent-based coatings by introducing a polyaniline-graphene oxide (PAGO) composite into ZWC. The PAGO composite was prepared by in situ polymerization of aniline in the graphene oxide (GO) suspension. Polyaniline (PANI) was evenly distributed in the GO lamellas, which would benefit the uniform dispersion of PANI in aqueous solution. The anticorrosive performance of PAGO-ZWC was analysed and compared with that of pure ZWC, PANI modified Zinc-based waterborne coatings (PANI-ZWC) and GO modified Zinc-based waterborne coatings (GO-ZWC). PAGO could enhance the conductivity of water-based resin, and then facilitated the zinc powder to be linked with the conductive network. The cathodic protection and barrier performance of ZWC were significantly improved by introducing a small amount of PAGO (0.5 wt.% PAGO) into the Zinc-based waterborne resin compared with that of the PANI- ZWC and GO-ZWC, leading to the most effective corrosive resistant of PAGO. The excellent anticorrosion durability was due to the superior dispersibility, high conductivity and good barrier property of PAGO that blocked H2O, O2 and electrolytes from penetrating to the steel substrate.