Unveiling the mechanism of structure-dependent thermal transport behavior in self-folded graphene film: a multiscale study

Understanding the relationship between the microstructures and overall properties is one of the basic concerns for 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 remained unclear. We here develop a theoretical model to describe the thermal transport behavior in SF-GF. Our model demonstrates the relationship between the fold length of grafolds and thermal properties of SF-GF. It serves as an efficient and portable tool to predict the temperature profile and thermal conductivity of SF-GF with good validations by large-scale molecular dynamics simulations. Using this model, we further study the evolution of thermal conductivity of SF-GF with the unfolding deformation during the stretch. Moreover, the effect of geometrical irregularity of grafolds is uncovered. The model developed in this work not only provides practical guidelines for the manipulation and design of thermal properties of SF-GF, but also benefits the understanding of thermal transport behaviors in other two-dimensional nanomaterials with folded structures.