On the incorporation of the various reduced graphene oxide into poly(vinyl alcohol) nano-compositions: comparative study of the optical, structural properties and magnetodielectric effect

摘要

In this article, we report the significant results of the optical properties, structural properties, dielectric effect in different reduced graphene oxide (rGO)-doped poly(vinyl alcohol) (PVA) nanocomposites. The novelty of this work is the investigation of large-scale optical transparency, band structure parameters, conductivity property and magnetodielectric effect in detail for the various PVA-rGO nanocomposites. In order to the study optical as well as structure properties and morphology of PVA-rGO nanocomposites, UV-visible and Raman spectroscopy, XRD, and FESEM were used. The optical bandgap, Urbach energy of the nanocomposites has been studied. The refractive index, optical dielectric constants, optical conductivity of PVA, GO, rGO and PVA-rGO nanocomposites were investigated. The crystalline size (L_a) of the nanocom-posite membrane-type layer structures was varied from 15.76 to 20.45 nm. The Raman experiment showed lower D-band intensity with higher L_a and lower G-band intensity with lower L_a. The visual structures of the nanocomposites are observed from FESEM study. The dielectric constant study showed an increase in nature with increment of rGO content at a particular frequency. The conductivity of the PVA-rGO nanocomposite films has been increased from 0.5 to 2.58 micro-S/m at frequency (f) = 10 kHz whereas at f = 100 kHz, this value changed from 0.8 to 4.6 micro-S/m. The dielectric property of the nanocomposite with different weight percentage of rGO content was studied under different magnetic field (H = 0-1.2 T). From these data magnetodielectric effects are obtained as the variation of real (ε') and imaginary (ε") parts of complex dielectric constant with H at some frequencies. In our study at a frequency 100 kHz for the increase of H from zero to 1.2 T ε' decreases by 1.66% in PVA-rGO nanocomposite with rGO 0.5 wt%, and this value significantly increases up to 6.05% with the 8 wt% rGO content within the nanocomposite.