Find the maximum thermal conductivity of graphene reinforced polymer composite: A molecular dynamics approach

The ultrahigh in‐plane thermal conductivity makes the graphene nanoplatelet a promising reinforcement filler for improving the thermal conductivity of polymer materials. Up to now, the highest thermal conductivity enhancement has been achieved by aligning the nanoplatelets along the heat flux direction. In this work, extensive molecular dynamics simulations are carried out to understand the thermal conductivity enhancement capabilities of different architectures of the graphene nanoplatelets within the polyamide‐6 matrix. Surprisingly, we find that the orthogonally arranged graphene nanoplatelets offer even better thermal conductivity enhancement than the simply aligned graphene nanoplatelets. An in‐depth investigation shows that the orthogonal structure can achieve a balance between the global percolation and the alignment of graphene nanoplatelets. Specifically, such an orthogonal structure can take advantage of both thermal percolation and graphene's ultrahigh in‐plane thermal conductivity. Moreover, we have systematically investigated the effects of the size and number density of the nanoplatelets on the thermal conductivity enhancement capability of the orthogonal configuration. Finally, by proposing a validated analytical model, we have identified the pathways to maximize the thermal conductivity of the orthogonally arranged graphene nanoplatelets. The conclusion of this work points out the possible way to develop the graphene‐polymer composite system with exceedingly high thermal conductivity.