Graphene oxide functionalised with conducting and non-conducting polymer materials for spintronic and biomedical applications

Abstract

We have synthesised graphene oxide (GO) using Hummer’s method which was further reduced (rGO) by hydrazine hydrate. We used the reverse micelle process to functionalise graphene oxide (GO) to synthesise P-GO and its subsequent reduction produced P-rGO. The synthesised GO was coated with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) conducting polymer (CP) to obtain CP-GO which was subsequently reduced using hydrazine hydrate to form CP-rGO. We used Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), ultra-violet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) techniques to study the electronic and structural properties of GO, rGO, P-GO, P-rGO, CP-GO and CP-rGO nanocomposites for biological/biomedical applications. The magnetic properties of the nanocomposites were investigated using the superconducting quantum interference device (SQUID). The electrical conductivity of the CP-GO nanocomposites was found to be ~104 times higher than that of GO. The P-rGO nanocomposites exceptionally show an over-trebled magnetic response of 9.6 × 10-3 emu/g as compared to the CP-GO of 2.9 × 10-3 emu/g, respectively at 2 K. Functionalisation of GO with polyacrylate improves the magnetic properties for P-GO and P-rGO due to increase in defect density, sp3-type bonding and improved magnetic coupling of magnetic moments emanating from the presence of nitrogen species. The presence of polyacrylate and PEDOT:PSS contribute to the successful modification of the electronic and magnetic behaviour of the nanocomposites thereby qualifying them for potential biological/biomedical applications.