  The author reports an experimental study of electrical and thermal transport
in reduced graphene oxide (RGO)/polystyrene (PS) composites. The electrical
conductivity ($\sigma$) of RGO/PS composites with different RGO concentrations
at room temperature shows a percolation behavior with the percolation threshold
of ~ 0.25 vol.%. Their temperature-dependent electrical conductivity follows
Efros-Shklovskii (ES) variable range hopping (VRH) conduction in the
temperature range of 30 to 300 K. The thermal conductivity ($\kappa$) of
composites is enhanced by ~ 90 % as the concentration is increased from 0 to 10
vol.%. The thermal conductivity of composites approximately linearly increases
with increasing temperature from 150 to 300 K. Composites with a higher
concentration show a stronger temperature dependence in the thermal
conductivity.

Materials Science