Electric-field assisted growth and mechanical bactericidal performance of ZnO nanoarrays with gradient morphologies

Abstract In response to the widespread bacterial threat, mechanical bactericidal nanostructures with various morphologies have been reported for years. However, the relationship between morphology and bactericidal properties is still yet to be elucidated due to the lack of a fair comparison under similar density of the nanostructures. For this purpose, an electrical-field assisted hydrothermal growth method were utilized to prepare the ZnO nanoarrays with similar array density (1.9×10⁹ rod·cm²-2.4 ×10⁹ rod·cm²) but gradient morphologies from hexagonal prism, hexagonal prismoid to hexagonal pyramid on stainless steel sheets. Moreover, in dark condition, a bactericidal activity was observed on the ZnO nanoarray surfaces within 30 min contact for both E. coli and S. aureus cells. The bactericidal rate was rapidly enhanced as the average tip width of the nanorods decreasing from 137 to 38 nm. These results suggest that the hexagonal pyramid ZnO nanoarrays have a rapid, efficient and broad-spectrum bactericidal activity, which could contribute to the next-generation aquatic pathogens control strategies.