Synthesis and in-vitro antibacterial properties of the novel Ag wires reinforced carbon based composite coatings

Novel Ag wires reinforced composite coating is developed using a novel active screen plasma co-alloying process in the plasma ambient of methane and hydrogen, and silver wires were in-situ formed through a sputtering process. Scanning electron microscopy and transmission electron microscopy were applied to investigate the microstructures of the Ag wires and the composite coatings. It revealed that the Ag wires were randomly embedded in the composite coating which were formed by aggregated nano-Ag, whilst the composite coating was formed with silver, stainless steel and carbon. X-ray diffraction and X-ray photoelectron spectroscopy (XPS) were utilised to characterise the phases and chemical states of the composite coatings, which verified the metallic form of Ag and non-chemical bond between deposited metals and carbon. A vapor-solid mechanism was applied to explain the growth of the Ag wires during the duplex deposition. Excellent bactericidal effects of the composite coatings against both Gram-negative P. gingivalis and Gram-positive S. epidermidis bacteria were acquired through contacting with coated metallic samples.