Study on the Effect of UV Exposure on WO 3 /PVA based Nanocomposite Films

In the present work, Polyvinyl Alcohol (PVA) polymer has been chosen as a host matrix to incorporate tungsten trioxide (WO₃) nanofillers for synthesizing self-supporting and flexible nanocomposites (NC_S). WO₃ has been synthesized using the hydrothermal treatment and subsequently WO₃/PVA based NCs were prepared via solution casting technique. To ascertain the morphology and structure of fabricated NCs, scanning electron microscopy (SEM) and X-Ray Diffraction (XRD) techniques were used. Further, XRD data has been analyzed to calculate the crystallite size (nm) of WO₃ powder. The SEM micrograph depicts the rod-like morphology of the prepared sample. The optical parameters like band gap (E_g), refractive index (n), and optical conductivity (σ_opt) of prepared NCs were computed using optical data. Transmittance (%) of prepared NCs has been found to decrease with increasing wt% of WO₃ in PVA in UV regime highlighting their potential application in UV shielding devices. To study the effect of UV exposure on prepared NCs, optical spectroscopy has been used in diffuse reflectance (%) mode. The prepared NCs exhibit a significant decrease in diffuse reflectance (%) with increasing UV exposure time. Coloration efficiency (η_ph) of the WO₃/PVA NCs has been calculated using optical data. Coloration efficiency (η_ph) of 10 wt% WO₃/PVA NC film is (~ 0.1099) and decreases with a decrease in wt% of WO3 in PVA.