Mechanical and thermal properties of graphene random nanofoams via Molecular Dynamics simulations

Abstract

Graphene foams have recently attracted a great deal of interest for their possible use in technological applications, such as electrochemical storage devices, wearable electronics, and chemical sensing. In this work, we present computational investigations, performed by using molecular dynamics with reactive potentials, of the mechanical and thermal properties of graphene random nanofoams. In particular, we assess the mechanical and thermal performances of four families of random foams characterized by increasing mass density and decreasing average pore size. We find that the foams' mechanical performances under tension cannot be rationalized in terms of mass density, while they are principally related to their topology. Under compression, higher-density foams show the typical slope change in the stress–strain curve at 5−10% strain, moving from linear elasticity to a buckling region. At variance, lower density foams display a quasi-linear behavior up to 35% strain. Furthermore, we assess the thermal conductivity of these random foams using the Green–Kubo approach. While foam thermal conductivity is affected by both connectivity and defects, nevertheless we obtain similar values for all the investigated families, which means that topology is the critical factor affecting thermal transport in these structures.