This work shows the influence of several reactional parameters for obtaining graphene through successive steps of oxidation and exfoliation of bulk graphite (resulting in graphene oxide), followed by chemical reduction. The results showed that changes in temperature, reaction time, reducing agent and source of primary graphite lead to different surface compositions and stability in dispersion of graphene oxide. Also, the use of different reducing agents promoted different degrees of restoration of C=C bonds in the bidimensional structure of graphene.

Thin films of multiwalled carbon nanotubes/polyaniline nanocomposites (CNT/PAni) were synthesized through the liquid/liquid (L/L) interfacial route, deposited over glass substrates, and evaluated through cyclic voltammetry and amperometry as electrochemical sensor, using L-ascorbic acid as probe. Films with three different CNT/PAni ratios have been prepared. After the spectroscopic and morphological characterization, the electrochemical sensitivity towards L-ascorbic acid was evaluated and compared with similar sensors prepared from neat multiwalled carbon nanotubes (MWCNT) or neat polyaniline (PAni). The nanocomposite film that presented the best nanotube dispersion through the polymeric matrix presented the higher sensor sensibility, 0.237 µA (µmol L−1)−1 and a limit of detection (LOD) of 7.91 µmol L−1. These results evidenced a synergistic effect among the components, and the best response depended on strict control of the polyaniline matrix distribution surrounding the nanotubes.