Optical and Dielectric Performance of Green-Synthesized TiO 2 -Reinforced PVA–PVP–Chitosan Nanocomposite Films

This research work presents the optical and dielectric properties of poly vinyl pyrrolidone (PVP) polyvinyl alcohol (PVA) and chitosan (CS) polymeric films reinforced with TiO 2 nanoparticles produced green synthesis using Ocimum tenuiflorum (Thulasi leaf) extract. TiO 2 (Titanium dioxide) nanoparticles were integrated with the polymeric solutions at concentrations ranging from 0.025, 0.050, 0.075, and 0.1 wt% using a facile solution-casting method. Optical properties such as transmittance, absorbance, band gap energy (Eg), and dielectric parameters were systematically analyzed using UV–Visible spectroscopy (400–800 nm). The results exhibit that increasing TiO 2 load significantly enhances UV absorbance and dielectric constant. All synthesized polymeric films show relatively stable transmittance in the visible range (400–800 nm). Polymeric films with TiO 2 load (0.025 and 0.050 wt %) exhibit lower transmittance, indicating stronger polymer-nanoparticle interfacial interactions. In contrast, the films loaded with 0.075 and 0.1 wt% of TiO 2 show improved optical transparency, attributed to better nanoparticle dispersion and decreased light scattering. The obtained optical band gap values vary between 3.10 and 3.37 eV, reflecting changes in electronic structure induced by TiO 2 incorporation. Optical dielectric analysis reveals, increase in permittivity with TiO 2 addition, especially 0.050 wt% TiO 2 exhibits the highest dielectric constant due to enhanced interfacial polarization. These parameters collectively demonstrate that TiO 2 -reinforced PVA-PVP-CS films reveals tunable optical and dielectric characteristics that can be used in UV-shielding and optoelectronic coating.