Edge effect on interlayer shear in multilayer two-dimensional material assemblies

Abstract

Multilayer two-dimensional (2D) material assemblies (MLMs) with a staggered architecture are widely applied to transfer exceptional properties of 2D materials into their 3D counterparts. However, the quantitative relation between interlayer shear and structural deformation, significant for the design of high-performance MLMs, has not been fully understood due to the inadequacy of existing theoretical model. Integrating the nonlinear shear-lag model and molecular dynamics (MD) simulations, we here investigate the intricate interplay between in-plane deformation and interlayer shear of multilayer assemblies of graphene, molybdenum disulfide (MoS2), and hexagonal boron nitride (h-BN). It demonstrates that the classical shear-lag model can well describe the in-plane deformation of multilayer MoS2 assembly, but fails for multilayer graphene and h-BN assemblies due to the edge effect induced by the interlayer van der Waals attraction. Then, a modified shear-lag model accounting for the edge effect is proposed to quantitatively reveal the respective contributions of the interlayer sliding, edge-effect shear stress and the elasticity of 2D material platelet on the deformation of MLMs. We find that, under the framework of shear-lag model, the inexplicit edge-effect shear stress can be described by two characteristic constants, extremely simplifying the expression of edge-effect shear stress in practical engineering applications.