Study On The Regulation Of The Three-dimensional Topography Of The Substrate On The Wrinkling Behavior Of Graphene

As a two-dimensional nanomaterial,graphene not only has a high Young’s modulus(1.1 TPa)and mechanical strength,but also its excellent performance in optical and electrical fields has inspired graphene in many fields.Potential applications.Monoatomic layer graphene has extremely low bending stiffness and is prone to wrinkling.But the Wrinkles of graphene will seriously affect its stability and reliability as a nano device.However,accurately predicting the Wrinkle behavior of graphene on substrates with different surface morphologies is still a huge challenge.In this paper,the continuum mechanics theory and molecular dynamics simulation method are mainly used to study the Wrinkle behavior of graphene on substrates with different morphologies.The main research contents and results are summarized as follows:(1)The Wrinkle behavior of single-layer and multi-layer graphene sheets on substrates with different morphologies was studied using continuous medium mechanics and molecular dynamics methods.Compared with the flat substrate,due to the unevenness of the surface of the substrate,the van der Waals interaction on the graphene surface is not uniform,causing it to wrinkle.Based on the continuum mechanics theory,the mechanical model of the system is established in this paper.The exact expression of the adhesion energy between graphene and the substrate is obtained from the interlayer van der Waals interaction(vd W)based on Gauss quadrature,and the wrinkles of graphene are found.The behavior is mainly determined by the competition between interface adhesion energy,bending energy and strain energy.At the same time,the molecular dynamics results are consistent with the theoretical results.In addition,the Wrinkle changes of graphene sheets under different elastic substrates are also analyzed in this paper.The results show that as the Young’s modulus of the substrate increases,the consistency of graphene and substrate gradually weakens.(2)A calculation model for the bending stiffness of multilayer two-dimensional nanomaterials is proposed.The model considers the effect of the van der Waals interaction between layers on the in-plane strain of the two-dimensional nanomaterials,and more accurately calculates the bending stiffness of the multilayer two-dimensional nanomaterials.On the basis of this model,the competitive relationship between the adhesion energy of multilayer graphene on the morphology substrate,the bending energy and the shearing effect between layers is obtained.The results show that as the number of multi-layer graphene layers increases,the influence of the morphology base on its wrinkling behavior gradually weakens.And through different placement methods,the effect of the interlayer shearing of multilayer graphene on its wrinkling behavior is obtained.The results of this study provide a reliable theoretical model for understanding the interface between two-dimensional nanomaterials and three-dimensional topography and the design and assembly of graphene flexible nanodevices on the substrate.