There is an increasing interest in reducing bacterial harmfulness in recent years. Infection of medical devices and treatment rooms can cause significant morbidity and mortality. Having antibacterial surfaces such as silver and copper coated areas reduce the risk of bacteria growth considerably. In the current study, wire arc spraying technique has been utilized to produce an ultra fine microstructure antibacterial copper coating on metal substrate (stainless steel 316L) and none-metal substrate (MDF) for antibacterial applications. The chemical composition, microstructure, and surface morphology of copper coatings were characterized by X-ray diffraction (XRD) and scanning electron microscope (equipped for energy dispersive spectroscopy). Determination of the thickness and adhesion of the coatings were investigated experimentally. The roughness and wettability of surfaces were characterized using Surface Roughness Inception and dynamic contact angle meter. The surface free energy was calculated by Chibowsky model. In order to evaluateandcompare the behavior ofthe wettability, all samples were characterized by Will Helmi model. Copper coatings showed lower contact angle and higher surface free energy in comparison to stainless steel 316L and a micro grain structure of the commercially available copper.The influence ofmicrostructureandgrain size,urfaceropertieuch acontact angle, wettability,andurface freeenergy as well aurface roughness on the antibacterial behavior were investigated. In addition, crystallographic defects such as porosity and oxide contentof copper coatings oon-metallicubstrate(MDF), and metal substrate(stainless steel316L)were investigated by Image tool 3.00 software. The antibacterial properties of copper coatings was analyzed by both gram negative Escherichia coli and gram positive Staphylococcus aureus. The antibacterial performance of coatings was compared to stainless steel 316L and a micro grain structure of the commercially available copper. Results indicated that as-sprayed copper coatings have an excellent antibacterial behavior compared to stainless steel and micro grain copper sample which can be contributed to a fine grain size and existance of defects and micro pores in the microstructure. Reduction in bacterial numbers of E. coli and Staphylococcus aureus after contact with the three different surfaces indicated that E. coli was more sensitive to the inhibitory action of the copper coating (97% after 6 h), whereas S. aureus needes longer time to reach a similar percentage of the reduction. The killing rate for stainless steel is in the range of 8–24 h. The surface of the copper coating has high hydrophilic among other surfaces such as stainless steel 316L and a micro grain structure of the copper. Statistical analysihowed thattheantibacterialroperties of copper coatingwere significantly much higher than other samples . The material surface characteristics including the high surface roughness, the high surface free energy, the low contact angle and the chemical composition play a key role in increasing the antibacterial behavior of the surfaces. Keywords : Copper, Antibacterial, As – sprayed coating, Wire arc spray, Ultrafine grain, Wettability.
