The influence of the Samples thickness on the structural and optical properties of Polyvinyl Chloride/Zinc Oxide Nanocomposite Films: Application in catalytic degradation of methylene blue dye.

Abstract

Considered Technique spin coating of the most important techniques used to prepare thin films because it is easy to use and inexpensive since it is closely dependent on the number of layers deposited. This work aims to study the effect of samples thickness for nanocomposites of polyvinyl chloride doped with zinc oxide nanoparticles on the structural, optical properties, and photocatalytic activities. Nanocomposite films of polyvinyl chloride (PVC) - zinc oxide (ZnO) with a different number of the deposited layers (15, 20, 25, and 30 layers) were synthesized by a sol-gel method (spin coating) using tetrahydrofuran as a solvent, and investigated by various techniques. X-ray diffraction measurements indicated in the case of 15, 20, and 25 layers do not clearly show the presence of diffraction peaks. On the other hand, in the case of 30 layers, the presence of several peaks is observed, which testify to the presence of ZnO crystallites of wurtzite structure in PVC films. The size of the crystallites is almost equal to 32 nm depending on the working conditions. Raman and infrared spectra confirmed the result of X-ray diffraction on the incorporation of ZnO crystallites in the films produced by showing peaks corresponding to the modes of vibration of the crystal lattice of the ZnO doping semiconductor. Optical transmittance spectra have shown that The layers obtained have an optical transmission varying from 75 to 86% in the visible region of the spectrum. The values of the band gap energies, determined from the transmission spectra for the films deposited on glass, vary between 3.45 and 3.94 eV. The Photoluminescence spectra of ZnO/PVC nanocomposites studied revealed a strong ultraviolet and green luminescence, attributed to structural defects in the zinc oxide. The photocatalytic reaction has been shown using MB in the UV irradiation action of films stacked in an MB solution. The result showed that the 30-layer (PVC / ZnO) sample gave an efficiency to remove MB of 79% at 60 min, Similar to other samples which gave a lower efficiency.