Pore-penetration enabled ultrahigh interfacial thermal conductance between polyethylene and carbon honeycomb

B Liu and LB Yang and LY Feng and RH Zhou and QH Fang, COMPUTATIONAL MATERIALS SCIENCE, 236, 112864 (2024).

DOI: 10.1016/j.commatsci.2024.112864

This work investigates the interfacial thermal conductance (ITC) between carbon honeycomb (CHC) and polyethylene (PE) in a PE-based composite filled with CHC using molecular dynamics simulation. It is observed that the penetration of PE chains into the inner pores of the CHC filler leads to an ultrahigh ITC at the CHC-PE interfaces which can be one order of magnitude higher than the previously reported ITC at the interfaces between graphene and polymers. Correspondingly, the thermal conductivity of the composite is significantly enhanced compared to pure PE. Two main mechanisms are proposed to interpret these observations: 1) pore penetration of PE chains largely increases the effective contact area between CHC and PE; 2) permeation of PE chains across the porous CHC filler leads to the formation of direct contact between the PE chains on both sides of the CHC filler. The simulation results also show that, in combination with the interfacial thermal rectification effect, the penetration and permeation of PE chains across the CHC filler lead to asymmetric ITC on its two sides. In addition, the ITC shows nonmonotonic dependences on the density of the PE matrix and temperature, which have not been observed previously. Overall, the results presented in this work provide a new strategy to enhance the thermal conductivity of a polymer by filling it with nanoporous fillers and is helpful for developing advanced thermal conductive polymeric composites.

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