Effect of Solvent Polarity on the Physical Properties and Antibacterial and Antifungal Activity of TiO2 and Ag/TiO2 Nanoparticles

The study aimed to investigate the influence of solvent polarity (ethanol and distilled water (DW)) on modifying the shape, structure, size, and optical properties of TiO2 nanoparticles (NPs) and Ag-decorated TiO2 (Ag/TiO2) NPs in the chemical medium. It used new, straightforward, and cost-effective growth procedures-dependent solvothermal and hydrothermal methods to produce all samples. The as-synthesized samples were comprehensively characterized using FESEM, XRD, UV-Vis, and FTIR techniques. The findings indicate that the change in the polarity index of the precursor solution produced small and spherical TiO2 NPs with high density. Also, the growth of nanoparticles progressively decreased from 18.07 to 14.51 nm due to the increasing value of the solvent polarity of the reaction medium. Whereas, a lower polarity index of the reaction medium results in a reduction in the energy-gap (Eg) of pure TiO2 NPs from 3.76 to 3.33 eV. The study also estimated the antibacterial and antifungal activities of all as-grown samples and found that the Ag/TiO2 NPs exhibited excellent antibacterial and antifungal activity and selectivity against both Gram-positive and Gram-negative bacteria, as well as fungal micro-organisms when compared to pristine TiO2 NPs.