Biocompatible Poly(Vinyl Alcohol)-Copper Oxide-Graphene Oxide (PVA-CuO-GO) Nanocomposites: Synthesis, Structural and Optical Properties

Motivated by the unique combination of copper oxide (CuO) and GO (graphene oxide) nano-fillers with optimized composition in the PVA (poly vinyl alcohol) polymer, the studies in this paper have been directed towards the synthesis and characterization of (PVA-CuO-GO) polymer nanocomposites. The polymer nanocomposites, i.e., PVA-CuO-GO have been prepared by melt blending technique considering GO and CuO with variable wt.% (ranging from 0.5 to 3 wt.%). The composite was made in the shape of a dumble-like structure. To get the structural information, optical properties, surface morphology and available functional groups in the composites and their mechanisms, XRD (x-ray diffraction), UV-Vis-NIR spectrophotometer, photoluminescence (PL), FESEM (field emission scanning electron microscope) and FTIR (Fourier transform infrared) techniques have been used, respectively. From XRD data, the effect of wt.% of nano-fillers on crystalline size and micro-strain has been studied. The average crystalline size and micro-strain were calculated as similar to 32 nm and similar to 0.0250, respectively. From UV-Vis-NIR spectrophotometer data, tauc plots have been studied which tells that the increment in wt.% of nano-fillers causes the optical band gap to increase. On increasing the concentration of nano-fillers from 0.5 to 3 wt.%, the bandgap was increased from 2.5 to 2.8 eV. This tuning of bandgap can be supposed as fine tuning in near UV region. According to PL results, all the composites show a wide emission band in the UV-Vis region with the maximum at 487 nm when excited by 415 nm wavelength. Further, the luminescence intensity has been found to decrease with the addition of wt.% of the loading. The smoothness of the surfaces of the composites has also been studied with EDAX analysis. According to FTIR spectra, the available functional groups were found as: C-O, C-H stretch, C-H asymmetric stretch, C = O carbonyl stretch and C-H bending and deformation vibrations. In view of the characterizing results, the synthesized polymer nanocomposites can be used in several kinds of optoelectronics applications.