Robust multifunctional microcapsules with antibacterial and anticorrosion features

Corrosion and biofouling are two common unsolved problems in the marine industry, urging the need of innovative solutions to tackle both problems simultaneously. Herein, the fabrication of multifunctional microcapsules containing 8-hydroxyquinoline (8-HQ) as the corrosion inhibitors and clove oil as the natural antimicrobial compound is described to resolve both corrosion and biofouling problems simultaneously. Microcapsules containing 8-HQ and clove oil, featuring good mechanical properties, anticorrosion, and antibacterial properties, were successfully synthesized through in-situ polymerization of melamine-formaldehyde polymer. The fabricated microcapsules show antibacterial properties against Escherichia coli, Vibrio coralliilyticus and E. aestuarii, as revealed from the standard ASTM E2315 time-kill test. Multifunctional coatings with both antibacterial and anticorrosion features were fabricated by incorporating the fabricated microcapsules both onto and into the epoxy coatings. According to the zone inhibition test, the microcapsules-based multifunctional coating possesses antibacterial properties against the seawater bacteria. Manually scratched microcapsules-based multifunctional coatings possess anticorrosion properties, due to the formation of corrosion inhibition layer resulted from the reaction between the released 8-HQ compound and the mild steel substrate. Additionally, after 30 days of immersion in the salt water, the microcapsules-based coatings still possess anticorrosion properties by forming corrosion inhibition layer at the scratched region.