Poly (vinyl alcohol)/gold nanoparticle nanocomposite films: tunable optical response and calculated gamma-ray shielding performance

Abstract

Nanocomposite films containing 5–30 wt% gold nanoparticles were prepared by solution casting. Their optical properties and calculated gamma-ray shielding performance were investigated. XRD indicates that the films retain the semicrystalline structure of PVA, whereas FTIR indicates changes in the PVA bonding environment, consistent with a modified polymer network following Au incorporation. The UV–Vis–NIR spectra show enhanced absorption and a visible Au surface-plasmon-resonance band. Within the Au-containing series, two apparent Tauc transition energies decrease from 2.02 to 1.75 eV and from 3.15 to 2.27 eV as the nominal Au loading increases from 5 to 30 wt%. The refractive index, optical conductivity, and model-estimated linear and third-order optical susceptibilities increase across this series. The Phy-X/PSD calculations, based on nominal compositions and density inputs, predict increasing GMAC and Zeff, and decreasing GHVL and GMFP, with increasing Au loading, with a distinct Au K-edge feature near 80.7 keV (0.0807 MeV). PVA/30Au provides the best calculated attenuation parameters among the investigated nominal compositions. These calculations do not constitute experimental validation of gamma-ray transmission, and direct microscopic characterization is required to establish nanoparticle distribution.