Synthesis and characterisation of polyaniline and/or MoO2/graphite composites from deep eutectic solvents via chemical polymerisation

Abstract

Novel polyaniline (Pani) and/or graphite (Gr)/molybdenum dioxide (MoO2) composites have been successfully synthesised via an in situ chemical polymerisation method using a Deep Eutectic Solvent (DES) as the electrolyte. The chemical structure and properties of the Pani composites were characterised using various analytical techniques such as Raman, FTIR and UV–Vis spectroscopies, Thermo-Gravimetric Analysis (TGA), X-ray diffraction (XRD) and conductivity measurements, confirming its semi-crystalline nature. The results show shifts in the Raman, XRD and FTIR spectral features associated with the Pani composites, indicating that a matrix of metal oxide and/or graphite had formed in the polymer. Higher electrical conductivity was observed for the Pani/Gr (5.58 S cm−1) and Pani/Gr/MoO2 (9.87 S cm−1) composites compared to pure Pani (1.25 S cm−1). The homogenous growth of Pani chains on the graphite and MoO2 network were clearly observed by Scanning Electron Microscopy (SEM) and Energy Dispersive Analysis by X-ray (EDAX). A larger surface area and greater porosity were achieved in the Pani/MoO2, Pani/Gr/MoO2 and Pani/Gr samples, while a more compact structure was obtained for the Pani sample. These findings support that the idea that the polymer/graphite composites would be more useful for electrochemical charge transport, supercapacitance and energy storage applications compared to those using the pure polymer alone.