Evaluation of bio corrosion-resistant and antifouling properties of gold metallosurfactant monolayer on galvanised steel in simulated sea media inoculated with halophiles

Abstract In order to grow a novel kind of antibacterial Au containing bioactive film with good bio corrosion resistance capability for galvanised steel (GS) we targeted a greener approach towards the synthesis of novel bishexadecyltrimethylammoniumaurate(III)bromide metallosurfactant and assessed its inhibitive action towards biofilm formation and corrosion in artificial sea water salts broth. The synthesized complex was characterised by spectroscopic tools like FTIR (near and far regions), and 1H NMR. Also, the thermo gravimetric measurements and elemental analysis were done to find out the metal content in the metallosurfactant. The successful fabrication of coatings and the changes in the surface chemistry of the substrate made by these coatings during biofilm formation was monitored by X-Ray Photoelectron Spectroscopy (XPS). Further, the hydrophobic nature of the coating was checked by the static water contact angle measurement. The antibacterial efficacy of the fabricated coating against Halobacterium salinarium and Halococcus morrhuae was assessed by Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). The Electrochemical Impedance Spectroscopy data and Tafel plots marked the coating as an efficient electrochemical corrosion inhibitor. The inhibition efficiency of coatings increases with the increase in the concentration of metallosurfactant solution because of the rise in the hydrophobicity due to the formation of metallomicelles and antibacterial activity of AuCTAB with which higher surface coverage of the films was formed (at higher concentration).