Graphene-supported carbonaceous dielectric sheets and their electrorheology

Two-dimensional dielectric sheets composed of graphene-supported amorphous carbon were prepared by annealing polyaniline-coated graphene oxide sheets in vacuum. The morphology and structure were characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and Fourier-transform infrared spectroscopy. This showed that annealing the polyaniline-coated graphene oxide had little influence on its plate-like morphology but transformed the graphene oxide core into conducting graphene and the polyaniline shell into insulating nitrogen-enriched amorphous carbon. An electrorheological suspension was prepared by dispersing the graphene-supported carbonaceous sheets in silicone oil and its electrorheological property was investigated by rhelogical tests under electric fields. The suspension demonstrated a strong electrorheological effect. Its yield stress and shear stress were about three times as large as those of a suspension of pure carbonaceous particles at equal electric field strengths. The storage modulus of the suspension was also higher than that of a suspension of pure carbonaceous particles, indicating stronger electrorheological activity.