Underwater superoleophobic composite coating characteristic of durable antifouling and anticorrosion properties in marine environment

Biofouling of marine vessels often results in low fuel efficiency and severe hull corrosion, an ecological friendly coating with long durability and high Benefit-cost is greatly desired to prevent biofouling and bioadhesion. Herein, a facile “Glue + Powder” strategy was employed to synthesize a composite coating with satisfactory oil-repellent and anticorrosion properties, in which the hexadecyl-trimethoxysilane modified SiO2 nanoparticles (NPs) act as superhydrophobic undercoating and polyacrylic acid modified ZnO NPs implanted in polydimethylsiloxane as superoleophobic finishing coat. Immersion tests evidenced that no obvious cracks appeared on the surface of the bifunctional composite coating, without apparent adhesion loss even after 30 d of immersion in 3.5% NaCl solution. Electrochemical tests demonstrated that the Al alloy electrode lacquered by the composite coating presents a high impedance (above 109 Ω cm2) even after 25 d of immersion in 3.5% NaCl solution, dramatically reducing the corrosion rate of Al alloy by 7 orders of magnitude. In addition, tribocorrosion test indicated that the coated Al alloy specimen can survive from 120 cycles of friction-wear under 0.5 MPa loading, exhibiting excellent corrosion and wear resistance. Antifouling test showed that the bifunctional composite coating could reduce the underwater adhesion of oily molecules with an oil contact angle of 160 ± 2°, presenting excellent superoleophobicity and immune of the adhesion of Pseudomonas sp. and following formation of biofilm. Hopefully, it could be one of competitive marine antifouling coatings.