Heat Transfer at the Interface of Graphene Nanoribbons with Different Relative Orientations and Gaps

Shahin Mohammad Nejad,Matteo Fasano,Masoud Bozorg Bigdeli,Rajat Srivastava

doi:10.3390/en12050796

Abstract

Because of their high thermal conductivity, graphene nanoribbons (GNRs) can be employed as fillers to enhance the thermal transfer properties of composite materials, such as polymer-based ones. However, when the filler loading is higher than the geometric percolation threshold, the interfacial thermal resistance between adjacent GNRs may significantly limit the overall thermal transfer through a network of fillers. In this article, reverse non-equilibrium molecular dynamics is used to investigate the impact of the relative orientation (i.e., horizontal and vertical overlap, interplanar spacing and angular displacement) of couples of GNRs on their interfacial thermal resistance. Based on the simulation results, we propose an empirical correlation between the thermal resistance at the interface of adjacent GNRs and their main geometrical parameters, namely the normalized projected overlap and average interplanar spacing. The reported correlation can be beneficial for speeding up bottom-up approaches to the multiscale analysis of the thermal properties of composite materials, particularly when thermally conductive fillers create percolating pathways.

Highlights

Carbon fillers such as carbon nanotubes and graphene nanoribbons are often suggested as possible additives in composite materials
Carbon-carbon bonded interactions were modelled by the adaptive intermolecular reactive empirical bond order (AIREBO) potential [45] implemented in the LAMMPS molecular dynamics package [46], whereas, non bonded van der Waals interactions between the graphene nanoribbons (GNRs) were modelled by 12-6 Lennard-Jones potential
The effect of relative orientation of isolated adjacent graphene nanoribbons on the thermal resistance at their interface has been systematically studied by reverse non-equilibrium molecular dynamics

Summary

Introduction

Carbon fillers such as carbon nanotubes and graphene nanoribbons are often suggested as possible additives in composite materials. These materials show a remarkable combination of superior thermal [1,2,3,4], electrical [5,6,7], lubrication [8,9] and mechanical [10,11,12] properties, which have the potential to significantly enhance the performance of base materials. Since the thermal conductivity (λ) of pristine polymers is generally low (0.11–0.44 W/m·K [20]), it would be expected that adding carbon nanofillers with high λ (100–5000 W/m·K [21,22]) would greatly enhance the effective thermal conductivity of the resulting mixture. The presence of defects (e.g., atom substitutions, atomic vacancies, Stone-Wales dislocations) [27], edge chirality [28], dumping due to the surrounding polymer [29], and interfacial thermal resistance (Rk , known as Kapitza resistance) at Energies 2019, 12, 796; doi:10.3390/en12050796 www.mdpi.com/journal/energies

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Discussion

Conclusion