Study on the Effect of UV Exposure on WO3/PVA based Nanocomposite Films

Abstract

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 (NCs). 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 (Eg), refractive index (n), and optical conductivity (σopt) 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 (ηph) of the WO3/PVA NCs has been calculated using optical data. Coloration efficiency (ηph) of 10 wt% WO3/PVA NC film is (~ 0.1099) and decreases with a decrease in wt% of WO3 in PVA.