Preparation of BTA@PDA/PANI microcapsules and anti-corrosion performance of self-healing epoxy coatings on low carbon steel

Benzotriazole-loaded polydopamine/polyaniline ([email protected]/PANI) microcapsules are prepared vis the combination of a hard template method and in-situ polymerization. The PDA/PANI hollow microspheres are first prepared using SiO2 as a hard template and etching them with hydrofluoric acid. The BTA corrosion inhibitor is then loaded into the PDA/PANI hollow microspheres to obtain the [email protected]/PANI microcapsules. The mean particle size and shell thickness of the synthesized microcapsules are 8.3 and 2.1 µm, respectively. The load capacity of BTA is above 20 wt%. The corrosion resistance of epoxy coatings with different contents and types of microcapsules is compared by saline immersion and electrochemical impedance tests. A scratched coating with 1 wt% [email protected]/PANI microcapsules has the best anti-corrosion effect. The synergistic anticorrosion mechanism of BTA, PDA and PANI is revealed and confirmed.