Fabrication of silanized GO hybrid coating on 316L SS with enhanced corrosion resistance and antibacterial properties for marine applications

Abstract

We report a facile approach for fabrication of hybrid silanized graphene oxide (SGO) coating on 316L stainless steel (SS) using organofunctional silane, (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and graphene oxide (GO). The barrier/antimicrobial property of GO and the insulating property of silane matrix are exploited to achieve the superior corrosion resistance and antibacterial properties for marine applications. The coating was characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and surface profilometer. SGO coating is formed through grafting of silanol on GO sheets and covalent metallic-siloxane bonding between metal surface and coating. With an optimum loading of 0.05 wt% GO, the coating gave an enhanced corrosion resistance, with a three order reduction in the corrosion current density as compared to uncoated SS surface. Confocal laser scanning microscope (CLSM) analysis showed no pit formation on the SGO coated specimens exposed in 3.5 wt% NaCl electrolyte on prolonged exposure for 28 days, as compared to numerous pits on the uncoated surface. A five order enhancement of antibacterial activity in gram-positive and gram-negative bacteria cultures is observed in SGO coated surfaces due to the adverse physicochemical interaction between GO and microbes, leading to the cell disruption or cell death. These results show the potential applications of silanized graphene oxide hybrid coating on 316L SS for marine applications.