Surface coating on aluminum substrate with polymeric guanidine derivative to protect jet fuel tanks from microbial contamination

Abstract Antimicrobial coatings can act as an effective barrier to microbial growth and colonization in jet fuel tanks, which can effectively avoid the safety problems and economic losses. In this study, we initially synthesized an antimicrobial and water-insoluble complex, poly (hexamethylene guanidine) hydrochloride-sodium stearate (PHMG-SS), and its minimum inhibitory concentrations (MICs) were measured as 0.25 g/L, 0.25 g/L, 0.25 g/Land 0.5 g/L against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Yarrowia lipolytica, respectively; then, PHMG-SS was facilely coated onto the surface of aluminum substrate by the aid of a green linker, polyvinyl butyral (PVB). The PHMG-SS-coated aluminum exhibited a powerful microbicidal activity against the above four microorganisms, and provided a greater than 99.999% (5 log) reduction in viable counts of experimental microorganisms within 30 min through contact. In addition, the antimicrobial performance could still be observed after 7 d of ultraviolet radiation or soaking in jet fuel. Furthermore, the antimicrobial mechanism was investigated and concluded as damaging the microbicidal morphologies and suppressing the activity of respiratory chain dehydrogenase. Finally, PHMG-SS-coated aluminum was evaluated as interior surface of jet fuel tanks to protect jet fuel, and the experimental results showed that PHMG-SS-coated aluminum achieved a greater than 99.9999% (6 log) reduction in viable counts of a mixed suspension of Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Yarrowia lipolytica within 30 min. The outputs from this work represent a highly versatile approach to build an antimicrobial barrier to protect jet fuel from microbial contamination, and such approach is also worthy of wide application to treat other surfaces.