Dual Anticorrosive and Self-healing Coating Based\non Multiresponsive Polyaniline Porous Microspheres

In\nthis work, a smart self-healing coating with long-term anticorrosion\nability was developed based on multiresponsive polyaniline (PANI)\nporous microspheres. The polyaniline porous microspheres loaded with\ncorrosion inhibitor (benzotriazole, BTA) was prepared by the emulsion\ntemplate method and photopolymerization. The BTA loaded in the polyaniline\nmicrospheres acted as a corrosion inhibitor, while the polyaniline\nin the shell performed the multiple functions of corrosion inhibition,\npH-responsive and photoresponsive release, and photothermal conversion.\nOwing to the inherent corrosion-inhibiting nature of BTA and PANI,\nthe BTA-loaded polyaniline microsphere could endow coating with dual\nanticorrosive properties. The coating with polyaniline microspheres\ndid not show any corrosion product after 700 h of salt spray testing,\nwhile obvious pitting corrosion could be observed for the blank coating\nafter 100 h of the salt spray test. Thanks to the photothermal properties\nof PANI, the composite coating exhibited self-healing behavior under\nNIR light irradiation. The coating with 10 wt % polyaniline microspheres\ncould achieve rapid closure and recover its barrier properties within\n5 s of NIR irradiation. And the release of BTA could form a passivation\nfilm on scratches to further repair coating defects. The on-command\nresponsive release, high healing efficiency, and excellent anticorrosion\nproperties of this dual self-healing anticorrosion coating provide\nperspectives on extending the service life of metals.