Fabrication of superhydrophobic SiO2/VS2 composite coating on anodized aluminum alloy and its self-cleaning, anticorrosion and antibacterial performance

To address the issues of severe corrosion (especially in chloride-rich marine environments) and microbial adhesion-induced biofouling that limit the service life of aluminum alloys, this study developed an integrated surface protection system for aluminum substrates by synergizing anodic oxidation and composite functional coating technologies. First, an anodized aluminum oxide (AAO) layer was constructed on 5052 aluminum alloy, then VS 2 micro-nano particles were synthesized via hydrothermal method while SiO 2 nanoparticles were hydrophobically modified with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES, denoted as P-SiO 2 ), and finally P-SiO 2 and VS 2 (optimal mass ratio of 3:1) were sprayed onto the AAO surface with epoxy resin as binder to form the organic-inorganic superhydrophobic composite coating (AAO@P-SiO 2 /VS 2 ). Multiple characterization techniques including XRD, XPS, FTIR, SEM, HRTEM, ICP-OES, laser particle size analyzer and surface roughness tester were used to systematically confirm the phase purity, elemental composition, valence state, micro-nano morphology, thickness, stoichiometry and roughness of the coating and its components. Performance tests showed that the composite coating exhibited excellent superhydrophobicity (water contact angle of 152.12°, sliding angle of 4.6°) and corresponding self-cleaning ability, significantly enhanced corrosion resistance (self-corrosion current density of 6.053 ×10⁻ 11 A/cm 2 , 1 order of magnitude lower than AAO and 5 orders of magnitude lower than bare aluminum alloy; low-frequency impedance modulus of 4.50 ×10 8 Ω·cm 2 ), outstanding antibacterial activity (99.89 % antibacterial rate against Pseudomonas aeruginosa , and effective inhibition against Escherichia coli and Staphylococcus aureus ) as well as good stability and durability (excellent wear resistance, high adhesion of 18.20 MPa, and water contact angle remaining above 150° after 30 days of immersion in 3.5 wt% NaCl solution). This study innovatively integrates anodization with PFDTES-modified SiO 2 and VS 2 -based antibacterial composite coating, providing a cost-effective and sustainable solution for enhancing the multifunctional protection of aluminum alloys, which is of great significance for extending the service life of metal equipment, especially in marine and harsh industrial environments.