Fabrication of superhydrophobic titanium surfaces with superior antibacterial properties using graphene oxide and silanized silica nanoparticles

Abstract

In spite of the superior corrosion resistance, titanium is prone to biofouling, especially in marine environment. Here we report a new approach to create robust superhydrophobic (SHP) Ti surfaces with superior antibacterial property, using silane containing silica nanoparticles (Si np) functionalized Graphene oxide (GO). Anodized titanium was first electrophoretically coated with GO, which is then coated with Si np dispersed perfluorooctyltriethoxy silane. The atomic force microscopic (AFM) investigations revealed an enhanced rms roughness of ~200 nm for silane functionalized silica nanoparticles deposited over graphene oxide coated surface as compared to 60 nm for GO alone coated surface. Laser Raman Spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS) confirmed that the silanized silica nanoparticles are covalently bonded to the graphene oxide sheet. The micro-nano scale roughness due to the distribution of Si np over the wrinkled sheets of GO along with the low surface energy silane moieties provided a water contact angle (WCA) of 173° with zero tilting angle. The silane-graphene oxide coated samples showed 3–5 orders lesser gram-negative Pseudomonas sp. and gram-positive Bacillus sp. on bacterial adhesion as compared to control sample. In addition, hybrid superhydrophobic titanium exhibited excellent chemical stability and mechanical durability in marine environment.