| Abstract [eng] |
During this study, the influence of different surface types on biological fouling in the Curonian Lagoon was investigated, as well as antibacterial activity against Gram-positive and Gram-negative bacteria. Additionally, samples of aluminum and copper metals with different surface properties were examined, including their contact angle with a water droplet, surface morphology, and its effect on the formation and stability of a vapor film, as well as hydrodynamic resistance. The results showed that surfaces coated with a superhydrophobic layer, especially Al+ZnOPMHS and Cu+ZnOPMHS, exhibited extremely high contact angles (up to 180°), which significantly influenced the formation and stability of the vapor film. Cooling dynamics experiments revealed that surface modification of both aluminum and copper (through texturing and coating with a ZnOPMHS superhydrophobic layer) reduced the critical temperature for the onset of the Leidenfrost effect and extended the lifetime of the vapor film. In the case of aluminum, the vapor film duration increased from short-lived (1 – 2 s) on polished surfaces to approximately 12 s when coated, at a sample temperature of 300 °C and water temperatures of 25 – 40 °C. For copper, the critical temperature decreased to 160 °C, and the vapor film duration exceeded 14 s when using the superhydrophobic coating. Hydrodynamic resistance studies demonstrated that the lowest resistance occurs at higher temperatures, while the falling velocity depends on surface treatment. For aluminum samples, the maximum velocity reached 1.021 m/s at a sample temperature of 300 °C and water temperature of 40 °C, whereas for copper it reached up to 2.152 m/s at 280 °C and 20 °C, particularly when superhydrophobic coatings were applied. These results confirm that the vapor film formed around the sample reduces friction between the surface and water. Furthermore, ZnOPMHS superhydrophobic coatings exhibited antibacterial properties, with the highest effectiveness against Gram-positive Bacillus subtilis (inhibition zone of 2.5 cm) and Gram-negative E. coli bacteria (inhibition zone of 1.9 cm). Biofouling studies showed that copper surfaces are resistant to fouling due to the presence of copper ions, while for aluminum surfaces, texturing and coatings reduced biofouling by 27.7% and 35.4%, respectively. |
