Novel long-acting smart anticorrosion coating based on pH-controlled release polyaniline hollow microspheres encapsulating inhibitor

• Long lasting polyaniline microspheres with pH-controlled release of MBT were prepared. • A smart self-healing coating based on the microspheres was fabricated. • The scratched smart coating exhibited excellent self-healing ability during 70 d. • The 180-d EIS proved the long-term anticorrosion effect of the intact smart coating. For the first time, the pH-sensitive polyaniline hollow microspheres encapsulating corrosion inhibitor 2-mercaptobenzothiazole (MBT@PANI) which could provide reliable controlled release of MBT for several months were incorporated with water-borne epoxy coating as smart filler. The EIS, SVET, XPS and salt spray test proved that the scratched MBT@PANI coating had relevant self-healing ability due to the responsive release of MBT triggered by the local pH increase caused by the corrosion. The 180-d EIS study confirmed that the intact coating also had expected long-term corrosion protection effect on aluminum alloy.