Physical insight in thermophysical features of gamma-irradiated PVA/Al2O3 films

Abstract

Herein, the synthesis and characteristics of polyvinyl alcohol (PVA) membrane reinforced with different alumina (Al₂O₃) nanoparticle concentrations before and after 100 kGy gamma irradiation for optoelectronic applications are described. FTIR spectra display the samples underwent discernible changes in their spectral structure because of the doping with Al₂O₃ followed by gamma exposure. This is due to the interaction between Al₂O₃ nanoparticles and the polymer matrix, which leads to the emergence of new absorption bands and a rise in the intensity of existing ones. SEM micrographs revealed that a dispersed collection of Al₂O₃ nanoparticles by homogeneity is present in the PVA matrix. Due to gamma exposure, the shape of the PVA/Al₂O₃ nanocomposite varies due to defects. Thermogravimetric analysis was used to evaluate thermal stability. Optical evaluations were carried out in the wavelength (200–1100 nm). It was shown that higher concentrations of Al₂O₃ followed by 100 kGy gamma-ray lead to the reduction in transmittance and higher absorbance levels in the PVA/Al₂O₃ membrane, especially in the UV-band. As the Al₂O₃ concentration grew, the direct and indirect bandgaps close from 5.40 to 5.30 eV and from 4.90 to 4.62 eV, respectively. After 100 kGy gamma-ray exposure the direct and indirect bandgaps dropped from 4.88 to 4.67 eV and from 4.02 to 3.63 eV, respectively. The improved optical parameters, specifically in terms of absorbance and bandgap manipulation, highlight the versatility of these nanostructures in various optoelectronic applications. It is noteworthy that there is an influence on the surface roughness parameters of the PVA membrane by Al₂O₃ nanoparticles and gamma exposure. As a result, the nanoparticles are nearly dispersed in the layer nearest the film surface, causing morphological changes as chemically active clusters and defects form on the membrane surface.