Relationship between surface properties and antibacterial behavior of wire arc spray copper coatings

Abstract

There is a trend towards reducing bacterial harmfulness in recent years. Infection of medical devices and treatment rooms can result in significant morbidity and mortality. Having antibacterial surfaces such as silver and copper coatings the risk of bacteria growth has been decreased, noticeably. In the current study, wire arc spraying technique was employed to produce an ultra fine microstructure copper coating on stainless steel 316L substrates. This paper examined the microstructure and surface micromorphology of copper coatings by scanning electron microscope (SEM). The chemical composition was evaluated by X-ray diffraction (XRD). The roughness, surface free energy and wettability of the surfaces were characterized using surface roughness meter inception, dynamic contact angle meter (tensiometer). The antibacterial property of copper coatings was analyzed by ATCC 25922 Escherichia coli (gram negative) and bacteria ATCC 29213 Staphylococcus aureus (gram positive) and then was compared to stainless steel 316L and the commercially available copper sheet. The relationship between the contact angle and surface free energy (SFE) and antibacterial properties was studied. Results indicated that as-sprayed copper coatings showed the best bactericidal activities. The material surface characteristics including the high surface roughness, the high surface free energy, the low contact angle and other characteristics such as ultrafine grain structure and the chemical composition play key roles in increasing the antibacterial behavior of the surfaces.