Thermal Stability and Optoelectronic Behavior of a Polyaniline-Graphene Nanocomposite

This study proposes the use of commercially available graphene nanoplates (GNPs) as a potential filler to optimize the bandgap energy of polyaniline (PANI). In situ cationic polymerization of PANI was performed with various concentrations of GNPs. The morphology, microstructure, and optoelectronic properties of the polyaniline-graphene nanoplates (PANI-GNP) composites were studied using numerous analytical tools. The in situ polymerization of aniline in the composites resulted in the exfoliation of stacked graphene sheets due to the intercalation of the polymer molecules among the graphene sheets and the H-bond interaction among residual functional groups on the graphene surface and the polymer. The thermal stability and electrical conductivity of PANI in the composites increased with increasing GNPs content, as evidenced by the thermogravimetry and DC electrical conductivity analysis. The bandgap energy of pure PANI and the composites was deduced using the Tauc equation. Incorporating GNPs resulted in decreasing the optical bandgap energy of PANI from 3.25 to 2.47, 2.36, and 2.34 eV in the 5%, 10%, and 15% PANI-GNP composites, respectively.