Molecular dynamics simulations of mechanical and thermal properties of multi-layer graphene sheets

Abstract

Graphene is a novel material that has leapt to the forefront of material science with its exciting intrinsic properties, creating new opportunities for numerous potential applications.

In this report, the effects of inter-layer sp3 bonding, temperature and number of layers on the mechanical and thermal properties of multi-layer graphene sheets have been studied by using non-equilibrium molecular dynamics.

Mechanical properties degrade linearly with temperature. Thermal energy increases the contribution to the total energy required for bond breaking. The mechanical properties experience also sharp degradation up to 5% inter-layer sp3 bonding. This is due to the hybridization of sp2 to sp3 bonds, resulting in long-range weaker bonds, thereby reducing the strain energy needed for breaking.

Thermal conductivity of the material is significantly affected by the inter-layer sp3 bonds. Thermal conductivity decreases by 50% up to the 5% inter-layer sp3 bonds. The increase in number of layers marginally decreases the thermal conductivity of graphene.

The work proposes that by controlling the amount of sp3 bonds, the mechanical and thermal properties can be fine-tune to design graphene-based nano-sized sensors, rectifiers and resonators.