ZnO nanoparticles were synthesized by the sol-gel method. The nanoparticles were added to polyvinyl alcohol (PVA) biopolymer to compare the microstructural, mechanical, antibacterial and physical properties of bionanocomposite films reinforced with various loading contents (1, 3 and 5 wt %) and thicknesses (70, 100 and 130 μm). Results showed that with increasing ZnO content to 3 wt %, the tensile strength and Young's modulus increased by 64 and 72%, respectively. The least amount of water vapor permeability was also observed in the sample containing 5 wt % ZnO nanoparticles. Moreover, the antibacterial properties of the films improved with ZnO addition and increased by increasing nanoparticle content up to 5 wt %. However, the transparency of the PVA-based films decreased by ZnO addition.

Sol-gel method was successfully used for synthesis of ZnO nanoparticles doped with 10 % Mg or Cu. The structure, morphology and optical properties of the prepared nanoparticles were studied as a function of doping content. The synthesized ZnO:(Mg/Cu) samples were characterized using XRD, TEM, FTIR and UV-Vis spectroscopy techniques. The samples show hexagonal wurtzite structure, and the phase segregation takes place for Cu doping. Optical studies revealed that Mg doping increases the energy band gap while Cu incorporation results in decrease of the band gap. The antibacterial activities of the nanoparticles were tested against Escherichia coli (Gram negative bacteria) cultures. It was found that both pure and doped ZnO nanosuspensions show good antibacterial activity which increases with copper doping, and slightly decreases with adding Mg.