Optical and Dielectric Performance of Green-Synthesized TiO₂-Reinforced PVA–PVP–Chitosan Nanocomposite Films

¹ Department of Chemistry, Thiagarajar College of Engineering, Madurai, Tamil Nadu, India
² Assistant Professor, Department of Chemistry, Thiagarajar College of Engineering, Madurai, Tamil Nadu, India
³ Professor & Head, Department of Chemistry, Thiagarajar College of Engineering, Madurai, Tamil Nadu, India

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

This research work presents the optical and dielectric properties of poly vinyl pyrrolidone (PVP) polyvinyl alcohol (PVA) and chitosan (CS) polymeric films reinforced with TiO₂ nanoparticles produced green synthesis using Ocimum tenuiflorum (Thulasi leaf) extract. TiO₂ (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 TiO₂ 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 TiO₂ 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 TiO₂ 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 TiO₂ incorporation. Optical dielectric analysis reveals, increase in permittivity with TiO₂ addition, especially 0.050 wt% TiO₂ exhibits the highest dielectric constant due to enhanced interfacial polarization. These parameters collectively demonstrate that TiO₂-reinforced PVA-PVP-CS films reveals tunable optical and dielectric characteristics that can be used in UV-shielding and optoelectronic coating.