Anomalous Thermal Response of Graphene Kirigami Induced by Tailored Shape to Uniaxial Tensile Strain: A Molecular Dynamics Study.

Hui Li,Yongjian Liu,Gao Cheng,Dan Zhong

doi:10.3390/nano10010126

Hui Li, Yongjian Liu + Show 2 more

Open Access

https://doi.org/10.3390/nano10010126

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Abstract

The mechanical and thermal properties of graphene kirigami are strongly dependent on the tailoring structures. Here, thermal conductivity of three typical graphene kirigami structures, including square kirigami graphene, reentrant hexagonal honeycomb structure, and quadrilateral star structure under uniaxial strain are explored using molecular dynamics simulations. We find that the structural deformation of graphene kirigami is sensitive to its tailoring geometry. It influences thermal conductivity of graphene by changing heat flux scattering, heat path, and cross-section area. It is found that the factor of cross-section area can lead to four times difference of thermal conductivity in the large deformation system. Our results are elucidated based on analysis of micro-heat flux, geometry deformation, and atomic lattice deformation. These insights enable us to design of more efficient thermal management devices with elaborated graphene kirigami materials.

Highlights

Strain engineering can effectively regulate the thermal conductivity of traditional bulk materials [1,2,3] as well as low dimensional nanomaterials [4,5,6,7,8]
We investigate investigate the thermal conductivity of kirigami graphene structures (KGS) using molecular dynamics simulations
Compared to the thermal conductivity of strain-free (ε = 0, κ0 = 2.9 W/mK), the actual deformation, the acoustic phonons with longer wave-length were involved with heat transfer thermal conductivity of square kirigami model (SKG) model (κ = 3.9 W/mK) along the x direction increased by 34.7% when the

Summary

Introduction

Strain engineering can effectively regulate the thermal conductivity of traditional bulk materials [1,2,3] as well as low dimensional nanomaterials [4,5,6,7,8]. For the most traditional materials, longitudinal deformation usually exhibits little effect on their variation of cross-section area in lateral direction. The effect of the minor variation of cross-section area deriving from longitudinal strain on thermal conductivity is small and can be negligible. Wei et al studied the effects of tailoring size on mechanical and thermal properties of KGS by introducing rectangular tailoring [11]. When material is conducted uniaxial tensile/compressive strain, it usually deforms in the lateral direction. The Poisson’s ratio is usually usually used used to to characterize characterize the the relationship relationship between the deformation deformation in the lateral direction for a material and its longitudinal strain.

Models

Schematic plot of of thethe reverse molecular dynamics method in calculating

Results and Discussion

Configuration

Configuration deformation ofKGSs

Conclusions