Highlights
Cu–Sn–TiO
2
nanocomposite coatings were electrodeposited under mechanical and ultrasonic agitation;
Effect of TiO
2
nanoparticles and current density on structural and antibacterial properties was investigated.
Distribution of TiO
2
in the coatings improved under ultrasonic agitation;
Antibacterial activity of Cu–Sn–TiO
2
coatings was enhanced by ultrasonic agitation.
In this work, Cu–Sn–TiO2 composite coatings were electrochemically obtained from a sulfate bath containing 0–10 g/L of TiO2 nanoparticles. The effect of TiO2 particles on kinetics of cathodic electrodeposition has been studied by linear sweep voltammetry and chronopotentiometry. As compared to the Cu–Sn alloy, the Cu–Sn–TiO2 composite coatings show rougher surfaces with TiO2 agglomerates embedded in the metal matrix. The highest average amount of included TiO2 is 1.7 wt.%, in the case of the bath containing 5 g/L thereof. Composite coatings showed significantly improved antibacterial properties towards E. coli ATCC 8739 bacteria as compared to the Cu–Sn coatings of the same composition. Such improvement has been connected with the corrosion resistance of the composites studied by linear polarization and electrochemical impedance spectroscopy. In the bacterial media and 3% NaCl solutions, Cu–Sn–TiO2 composite coatings have lower corrosion resistance as compared to Cu–Sn alloys, which is caused by the nonuniformity of the surface.
The morphology and composition of Ni-Sn and Ni-Sn-TiO 2 coatings have been studied by scanning electron microscopy and energy-dispersive X-ray analysis. The electrochemical behavior of the obtained coatings in a 3% NaCl solution has been examined. The influence of the inclusion of titania in the Ni-Sn coating on the mechanical and antibacterial properties has been revealed. Dependences of the influence of incubation time and exposure to UV radiation on the concentration of living bacteria cells on the surface of the Ni-Sn-TiO 2 coating have been established. In bacterial tests with Ni-Sn-TiO 2 coatings deposited from the electrolyte containing 2 g/L TiO 2 , the concentration of viable Staphylococcus aureus decreases from 130 to 90 CFU/mL and from 70 to 30 CFU/mL without and with UV irradiation, respectively.
Modern systems for the separate waste collection and recycling are not able to efficiently process all packaging materials in the composition of municipal solid waste, in particular, thin-walled products made from non-biodegradable polymeric materials. Reducing the share of such packaging and even refusing it has been enshrined in laws, it leads to development of new materials for these purposes, adequate criteria and methods for establishing biodegradability. The biodegradability of packaging material, consisting of starch, polylactide, and polyester of terephthalic acid, has been evaluated under conditions close to natural - in soil and in an aqueous environment. Packaging material degrades faster in an aqueous medium, biodegradation is more active in the presence of peptides, and mechanical destruction is faster achieved by alternating moistening with drying. Bacterial cultures had played the leading role in biodegradation, while cultures of microscopic fungi were practically not detected. This fact can be associated with the effect of photoinactivation of reactive oxygen species on the titanium oxide surface.
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