Effect of graphene nanoplatelets concentration on optical, dielectric and electrical properties of poly(2-ethyl-2-oxazoline)–polyvinylpyrrolidone–graphene nanocomposites

Abstract

The polymer nanocomposites with good optical, dielectric and electrical properties have taken faithfulness in research due to their distinguishing benefits in electronic applications. Hence, in the present investigation, poly(2-ethyl-2-oxazoline)–polyvinylpyrrolidone–graphene nanoplatelets (PEOX–PVP–GNPs) nanocomposites were synthesized and their properties were evaluated. Field emission scanning electron microscopy micrograph images showed a uniform dispersion of GNPs within the PEOX–PVP binary matrix. X-ray diffraction analysis illustrated the increase of crystallinity of nanocomposites with increasing weight percentage of GNPs. Fourier-transform infrared spectroscopy confirmed intermolecular interaction between the PEOX–PVP matrix and the GNPs. PEOX–PVP–graphene nanocomposite shows decrease in the optical energy band gap and increase in Urbach energy with increasing GNPs concentration. PEOX–PVP–10 wt% graphene nanocomposite has the lowest band gap (= 1.2 eV) and highest Urbach energy (= 7.43 eV). Dielectric constant, dielectric loss and tangent loss of nanocomposites decrease with increasing frequency of the applied electric field. On the other hand, the AC electrical conductivity of nanocomposites is independent of frequency, at lower frequencies, and increases with increasing frequency, at higher frequencies. PEOX–PVP–10 wt% graphene nanocomposite has the higher dielectric constant (= 16), low dielectric loss (= 0.09) and low AC conductivity (= 8.47 × 10−9 S/cm) at 1 kHz. This nanocomposite having good dielectric, electrical and optical properties may find use in electronic and optoelectronic applications due to its enhanced properties.