On shape-induced interfacial interactions in graphene/polyaniline composite produced through in situ polymerization approach

Reduced graphene oxide (rGO), polyaniline (PANI), and their composites are advanced nanomaterials widely used in flexible sensor fabrication. However, the interfacial interactions between graphene and PANI of different shapes/dimensionalities have been unknown. This study aimed to close this gap by hypothesizing that the stacking of PANI on rGO relies on its shape and is relatable to the composite's electrical properties. rGO was acted as a substrate for the in situ polymerization of aniline. Acidity of the polymerization medium was manipulated using H2SO4, CH3COOH, and distilled water (DW) to yield globule (0-D), tube (1-D), and plate (2-D) PANIs, respectively. Unique rGO-PANI nanocomposites with various stacking orientations were successfully produced. The distribution of PANIH2SO4 on rGO is more pronounced than PANICH3COOH and PANIDW, suggesting that the 0-D PANIs have better interfacial interaction with rGO than 1-D and 2-D PANIs. Only few 3-D PANIs were found to grow on rGO. The electrical conductance of rGO-PANIH2SO4 (3.34 × 10−4 S) was a thousand times greater than rGO-PANICH3COOH (6.52 × 10−7 S) and ten million times greater than rGO-PANIDW (6.89 × 10−11 S), attributed to both interfacial interaction and oxidation state of PANIs. The results were further verified and justified with FTIR and XRD analyses.