Abstract
The thermal conductance of graphene-matrix interfaces plays a key role in controlling
the thermal transport properties of graphene-based nanocomposites. Using classical molecular
dynamics simulations, we found that the interfacial thermal conductance depends strongly on the
mode of heat transfer at the graphene-matrix interfaces: if heat enters graphene from one side of
its basal plane and immediately leaves the graphene through the other side, the corresponding
interfacial thermal conductance, G(across), is large; if heat enters graphene from both sides of its
basal plane and leaves the graphene at a position far away on its basal plane, the corresponding
interfacial thermal conductance, G(non-across), is small. For a single-layer graphene immersed in
liquid octane, G(across) is ~150 MW/m2K while Gnon-across is ~5 MW/m2K. G(across) decreases with
increasing multi-layer graphene thickness (i.e., number of layers in graphene) and approaches an
asymptotic value of 100 MW/m2K for 7-layer graphenes. G(non-across) increases only marginally as
the graphene sheet thickness increases. Such a duality of the interface thermal conductance for
different probing methods and its dependence on graphene sheet thickness can be traced
ultimately to the unique physical and chemical structure of graphene materials. The ramifications
of these results in areas such as experimental measurement of thermal conductivity of graphene
and the design of graphene-based thermal nanocomposites are discussed.
