Multiscale modeling of heat conduction in graphene laminates

We developed a combined atomistic-continuum hierarchical multiscale approach to explore the effective thermal conductivity of graphene laminates. To this aim, we first performed molecular dynamics simulations in order to study the heat conduction at atomistic level. Using the non-equilibrium molecular dynamics method, we evaluated the length dependent thermal conductivity of graphene as well as the thermal contact conductance between two individual graphene sheets. In the next step, based on the results provided by the molecular dynamics simulations, we constructed finite element models of graphene laminates to probe the effective thermal conductivity at macroscopic level. A similar methodology was also developed to study the thermal conductivity of laminates made from hexagonal boron-nitride (h-BN) films. In agreement with recent experimental observations, our multiscale modeling confirms that the flake size is the main factor that affects the thermal conductivity of graphene and h-BN laminates. Provided information by the proposed multiscale approach could be used to guide experimental studies to fabricate laminates with tunable thermal conduction properties

Mechanical properties and thermal conductivity of graphitic carbon nitride: A molecular dynamics study

Graphitic carbon nitride nanosheets are among 2D attractive materials due to presenting unusual physicochemical properties.Nevertheless, no adequate information exists about their mechanical and thermal properties. Therefore, we used classical molecular dynamics simulations to explore the thermal conductivity and mechanical response of two main structures of single-layer triazine-basedg-C3N4 films.By performing uniaxial tensile modeling, we found remarkable elastic modulus of 320 and 210 GPa, and tensile strength of 47 GPa and 30 GPa for two different structures of g-C3N4sheets. Using equilibrium molecular dynamics simulations, the thermal conductivity of free-standing g-C3N4 structures were also predicted to be around 7.6 W/mK and 3.5 W/mK. Our study suggests the g-C3N4films as exciting candidate for reinforcement of polymeric materials mechanical properties