Sandwich-structured polyaniline-graphene-polyaniline two-dimensional hybrid sheets for polymer nanocomposites with high dielectric constant and low dielectric loss

Novel poly(methyl methacrylate) (PMMA) nanocomposites with high dielectric constant and low loss were successfully fabricated by using sandwich-structured polyaniline-graphene-polyaniline (rPANI-GS-rPANI) hybrids sheets as fillers. The hybrid sheets were obtained by two steps: aniline was first in situ polymerized on both surfaces of graphene oxide (GO) sheets and then the PANI-GS-PANI sheets were reduced by hydrazine. The fully reduced hybrid sheets were denoted as rPANI-GS-rPANI, which exhibit an insulator-conductor-insulator sandwich structure. It was found that, the rPANI-GS-rPANI based PMMA nanocomposites not only have high dielectric constant but also show a low loss. For instance, the dielectric constant and dielectric loss of the nanocomposite are around 28 and 0.05 at 1 MHz, respectively, when the volume ratio of GS to PMMA is 6 vol%. This study not only provides a new way to prepare polymer nanocomposites with high permittivity and low dielectric loss, but also expands the application space of graphene based fillers.