Significantly improved dielectric properties of bio-compatible starch/reduced graphene oxide nanocomposites

In this work, bio-compatible plasticized starch/reduced graphene oxide (PS/rGO) nanocomposite was fabricated using a facile aqueous casting method. Structural properties and surface morphology of the PS/rGO nano composites were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analysis which demonstrates increased degree of interaction between PS matrix and rGO. The UV-VIS spectroscopy reveals that the optical absorbance of the composite increases with the amount of rGO loading. The dielectric constant and AC conductivity of the nanocomposite was found to be significantly enhanced due to the incorporation of rGO nanofiller. The complex impedance spectra analysis shows an improved conductivity due to the incorporation of rGO which can be attributed to the change in bulk resistance together with a reduction in the relaxation time of the nanocomposite. A quantitative analysis from the fitting of the Cole-Cole plot revealed that incorporation of rGO into the nanocomposite reduces the grain boundary resistance from 1561 k Omega to 0.8 k Omega and increases the capacitive element form 0.12 nF to 2238 nF. The PS/rGO nanocomposites with improved dielectric properties synthesized by a simple, low-cost process will pave a way to the production of sustainable, bio-friendly flexible electronic devices.