Latex-based concept for the preparation of graphene-based polymer nanocomposites

The latex technology concept is applied for the preparation of graphene/polystyrene nanocomposites. Aqueous dispersions of graphene are obtained via oxidation and exfoliation of graphite and subsequent reduction in the presence of surfactant. The quality of the prepared nanofillers is characterized by atomic force microscopy (AFM). Different amounts of aqueous graphene dispersions are then mixed with polystyrene (PS) latex and composites are prepared by freeze-drying and subsequent compression molding. The final bulk and local conductivities of the composites are respectively measured by a four-point method and by means of conductive AFM (C-AFM) analysis. The morphology of the conductive nanocomposites is studied with charge contrast scanning electron microscopy imaging (SEM). The percolation threshold for conduction is below 1 wt% of graphene in the composites, and a maximum conductivity of about 15 S m(-1) can be achieved for 1.6-2 wt% nanofiller.