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

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.