A novel approach to calculate thermal expansion of graphene: Molecular dynamics study

High surface-to-volume ratio is one of the extraordinary physical parameters of graphene which plays a crucial role in its electronic, thermal, mechanical and chemical behavior. Despite a lot of continuing theoretical and experimental researches, there are properties of graphene which are not fully understood and known. One of these properties is the thermal expansion coefficient (TEC) of graphene which shows a quite different behavior from what is expected for ordinary materials and has been reported to have a negative value for a wide range of temperatures. All previous researchers have calculated the TEC of graphene by considering its projected size which decreases when the temperature increases. In this paper, a novel method has been used to report the TEC of graphene based on the calculation of its real surface area using molecular dynamics simulations. Our results make clear how much the real surface area of graphene varies with respect to the temperature which is applicable in designing graphene-based nanodevices.