Confinement of Functionalized Graphene Sheets by Triblock Copolymers

The confinement of functionalized graphene sheets (FGS) in the polystyrene (PS) domains of a nanostructured poly(styrene- b -isoprene- b -styrene) (SIS) block copolymer is reported in this paper. The addition of FGS showed a drastic effect on the nanostructured morphology of the block copolymer (BC) matrix switching from long-range order cylinders for the neat BC to cylinders parallel and perpendicular to the free surface for the nanocomposite. The confinement of the FGS was confirmed by atomic and electrostatic force microscopy. AFM images showed that only the PS block was able to sequester and host the graphene sheets due to chemical affinity. Moreover, the average diameter of the PS domains suggested that the FGS presented a stable folded configuration. The sequestering of the FGS by the PS block is associated to the measured increase of 6 °C in the PS glass transition temperature. EFM experiments revealed superficial electrical conductivity of the nanocomposites.