Prediction of structure-dependent thermal transport behavior in self-folded graphene film validated by molecular dynamics simulation

Abstract

Understanding the relationship between the microstructures and overall properties is one of the basic concerns for the material design and applications. As a ubiquitous structural configuration in nature, the folded morphology is also widely observed in graphene-based nanomaterials, namely grafold. Recently, a self-folded graphene film (SF-GF) material has been successfully fabricated by the assembly of grafolds and exhibits promising applications in thermal management. However, the dependence of thermal properties of SF-GF on the structural features of grafold has still remained unclear. We here develop an analytical model to describe the thermal transport behavior in SF-GF. Our model demonstrates the relationship between the geometry of grafolds and thermal properties of SF-GF. The predictions of temperature profile and thermal conductivity are well validated by molecular dynamics simulations. Using this model, we further study the evolution of thermal conductivity of SF-GF with the unfolding deformation during stretch. Moreover, the effect of geometrical irregularity of grafolds is uncovered. Interestingly, the predicted transport behaviors of SF-GF under stretch fit some analogous experimental observations reported in graphene-based strain sensor. Our results not only reveal the mechanisms behind some physical phenomenon in the applications of graphene-based devices, but also provide practical guidelines for the property design of SF-GF and other graphene assemblies with folded microstructure.