Antibacterial effect of nanostructured ZnO-SnO2 coatings: The role of microstructure

The article presents the study of transparent bactericidal ZnO-SnO2 coatings prepared on a glass surface by a polymer-salt method using polyvinylpyrrolidone, zinc nitrate, and tin (IV) chloride solutions. The coatings were studied by spectroscopic and luminescent methods, SEM, XRD analysis and their antibacterial activities against gram-positive (Staphylococcus aureus ATCC) and gram-negative (Escherichia coli ATCC 25922) were tested. Obtained ZnO-SnO2 films are thin (about 250-300 nm) and they fully cover the glass surface and contain oriented ZnO nanocrystals. Coatings crystal structure strongly affects their spectral and bactericidal properties. SnO(2)additions change the coatings microstructure by decreasing ZnO crystal size and making their spatial orientation more random. These microstructural changes enhance antibacterial activity against gram-positiveand gram-negative bacteria.