Self-protective Antibacterial and Hydrophobic ZnO Thin Film Coatings

Abstract

The Sol-Gel dip-coating technique was used to fabricate nanostructured ZnO thin-film coatings on amorphous glass substrates. To assess the impact of annealing temperature, the coated substrates were annealed at 400, 450, and 500 °C substrate temperatures respectively. X-ray diffraction, scanning electron microscopy, and optical double-beam spectroscopy were used to evaluate the effect of annealing temperature on the structural, morphological, and optical properties of the produced thin films. The disc diffusion technique and contact angle measurements were used to examine the obtained films’ hydrophobic characteristics and antibacterial activity. The obtained diffraction data revealed that all films have the polycrystalline hexagonal wurtzite crystal structure. When the annealing temperature was raised, it was observed that crystal grain sizes increased from 22.69 nm to 29 nm, indicating an improvement in crystallinity. The electronic micrographs clearly showed that the nanograins were evenly spaced over the film surface. Additionally, it was observed that increasing the annealing temperature resulted in a blue shift in the optical bandgap from 3.19eV to 3.09eV. The fabricated films showed increased antibacterial activity and hydrophobicity.