Novel graphene/hollow polyaniline carrier with high loading of benzotriazole improves barrier and long-term self-healing properties of nanocomposite coatings

Abstract

In this research, the main aim is to take the advantages of both graphene (Gr) and polyaniline (PA) in enhancing the barrier property and self-healing performance of composite coating. Herein, hollow polyaniline (HOPA) was prepared by sacrificing template method, which not only acted as a dispersant to enhance the dispersion of Gr nanosheets via the π-π interactions, but also was used as a nano container for storing benzotriazole (BTA) corrosion inhibitor. In addition, insoluble Cu-BTA complex stoppers possessed H+ ion-responsive inhibitor release property. The final release concentration of BTA in Gr/HOPA carrier was as high as 274.55 ppm, which was about 2.3 times than that of PA (120.42 ppm) due to the formation of cavity structure. From the EIS results of intact coatings, the 0.7 % of Gr/HOPA/BTA@Cu loaded composite coating exhibited a remarkable corrosion protection capability after 130 days of immersion. And the scratch test indicates that the Gr/HOPA/BTA@Cu based composite coating showed more long-term self-healing effect than that of Gr/PA/BTA@Cu/epoxy sample, which was related to the high BTA loading rate in HOPA.