Filtration technologies are of the highest interest for the human civilization, since they decrease the air pollution and can expand access to drinking water. Utilization of filtration methods is also important in food industry. However, in case of this application additional factor influences the life-time of membranes, which is bacteria and microorganisms growth. In order to limit these phenomena and increase the life-time of filter membrane, appropriate materials can be deposited on membrane surface. However, such coatings should be thin enough to avoid disturbance of the medium flow through the membrane, as well as pressure drop.  
During the work, different types of nanocrystalline ceramics coatings (CuO, AgO, ZnO and Cu+ZnO, Ag+ZnO, AgO+CuO) were deposited on model Si substrate using magnetron sputtering technique. Both, DC MS (Direct Current Magnetron Sputtering) as well as HPIMS (High Power Impulse Magnetron Sputtering) techniques were applied. The influence of deposition parameters e.g. cathode power on coating thickness, surface morphology, microstructure and chemical composition was analyzed. In the second stage, selected coatings were deposited on the filter membranes. The distribution of the deposited material on the membrane surface as well as interface between coating and substrate were analyzed. The antibacterial properties of the coatings were also investigated.
The investigation evidenced that the obtained coatings were characterized by homogeneous, nanocrystalline structure. However, deposited coatings differ microstructure and morphology. For example, CuO coatings exhibit columnar or needle like structure, while nano-grains in AgO coatings have more equized shape. Moreover, in case of multicomponent coatings (AgO+CuO), changes in the cathode (copper or silver) power results in differences in coating microstructure. The use of two sources leads additionally to composite structure (matrix and fine particles) of the coating. The performed investigation revealed also that application of HPIMS technique allows to deposit coatings of more homogeneous and less porous microstructure with smaller grain size compare to DC MS technique. All selected coating exhibits good antibacterial properties.
 
Acknowledgement: The research was financially supported by the Polish National Centre for Research and Development, grant no. TECHMATSTRATEG-III/0005/2019-00