Visibly transparent PVA/sodium doped dysprosia (Na2Dy2O4) nano composite films, with high refractive index: An optical study

The effect of varied weight fractions (0.0, 0.5, 1.0, 2.0 and 4.0) of sodium doped dysprosium oxide (Na2Dy2O4) nano fillers on the structural, gross morphological and optical properties of poly (vinyl alcohol) (PVA) films have been established by diverse spectral techniques. Fourier transform infrared (FT-IR) spectral studies ascertain the successful integration of metallic fractals of nano filler with the hydroxyl groups of the polymer. While, scanning electron microscopic (SEM) studies support excellent filler dispersions and contact angle measurements highlight the filler induced wettability transitions (hydrophilic (61.60 degrees) to near hydrophobic (89.02 inverted perpendicular)). The electronic spectral studies reflects the filler induced changes in the electronic band structure of PVA leading to decreased optical energy gaps from 4.25 eV to 3.55 eV, in addition to a systematic Refractive Index (RI) boost in line with Lorentz-Lorenz effective medium theory. The developed PVA/Na2Dy2O4 nano composites (NC) with high visible transparencies and higher refractive index (1.9 for 4 wt% PVA/Na2Dy2O4) alongside appreciable Abbe numbers are ideal optical materials for micro-optic and optical wave guiding applications. (C) 2016 Elsevier B.V. All rights reserved.