Synthesis of exfoliated conductive polyaniline–graphite nanocomposites in supercritical CO2

Exfoliated polyaniline–graphite nanocomposites with high electrical conductivity were synthesized. Graphite powders were first expanded with ScCO2 treatment and then aniline monomers were added to the suspension. The morphology and structure of the synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV/Vis spectroscopy and XRD analysis. SEM and TEM micrographs revealed that graphite was successfully expanded through ScCO2 treatment, and the graphite powders are fully exfoliated in the final nanocomposite. FTIR results confirmed formation of polyaniline (PANI), and UV/Vis analysis showed the conductive emeraldine state of the synthesized PANI. Furthermore, it was clearly demonstrated that ScCO2 medium does not have any effect on chemical structures of the PANI. The electrical conductivities of the PGNs enhanced dramatically with increasing graphite loading up to 40% and subsequently decreased due to the weaker bridged linkage between PANI and graphite layers at high graphite loading.