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.