The current paper focuses on investigating deformation mechanism of graphene sheets in a graphene reinforced polyethylene (Gn–PE) nanocomposite. Classical molecular dynamics (MD) simulation was conducted on large Gn–PE systems. Different spatial arrangements of graphene sheets were considered in order to study the effect of nonlocal interaction among the graphenes. In all the cases 5% weight concentration of graphene was considered in order to prepare atomistic models for Gn–PE.
In armchair graphene sheets, crack propagates perpendicular to the applied strain, whereas crack propagation in zigzag sheets occurs at an angle to the straining direction. This occurs due to different bond structure along armchair and zigzag directions as shown in Fig. 1. Videos 1 and 2 show the fracture of armchair and zigzag sheets, respectively.
Fig. 1: Armchair and zigzag directions of graohene
In this paper we attempt to answer two questions on graphene from a mechanic’s viewpoint: why does this one-atom-thick monolayer have finite bending stiffness to ensure its stability? and what is its wrinkle mechanism? As for the first question, it is found that the repulsive residual internal moment in the bond angle can lead to a nonzero bending stiffness, which makes the graphene flat. Together with long-range attraction among atoms, such as van der Waals forces, a graphene prefers to have a self-buckling wrinkled configuration with many waves.
A post-Doc position is available on a project on Ensemble Monte Carlo simulations of graphene for power electronics applications for studying the effect of boundary scattering of charge carriers in graphene nanoribbons. The project is sponsored by the Office of Naval Research- global (ONR) - Department of Defense (DOD)- U.S. Navy.
Several recent papers have reported measurements of adhesion energy between graphene and other materials (e.g., Si/SiOx and copper) [1-3]. Like thin films, many experimental methods may be adopted to measure the interfacial properties of graphene, such as the pressurized blister test [2] and the double-cantilever beam test [3]. The challenges lie in the handling of atomically thin membranes and analysis/interpretation of the data.
The mechanical behavior of mono- and multi- layered graphene and carbon nanotube (CNT) systems has attracted great attention over the last decade because of their importance in nano-science and nanotechnology.
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