Improvements of mechanical properties of multilayer open-hole graphene papers

Holes and defects can greatly reduce the mechanical properties of multilayer graphene sheets under different loading conditions due to the stress concentration near the hole edge in each in-plane sheet and the lack of interlayer carbon-carbon bonds between the layers. Here, we report a novel design of multilayer open-hole graphene papers (MLGPs) formed through interlayer covalent bonding at the hole edges of multilayer open-hole graphene sheets (MLGSs) under high temperature using molecular dynamics (MD) simulations. Our MD results show that the hybrid sp(2)-sp(3) interlayer bonds of MLGPs can significantly improve their both tensile strength and interlayer shear strength. The tensile strength and interlayer shear strength of MLGPs increase by around 20% and 3 times by comparison with those of MLGSs with the same number of layers, respectively, which mainly depends on the uniformity of their interlayer bond distribution. This study can provide an effective way to improve the mechanical performances of multilayer graphene sheets with flaws and also offer corresponding guidance for the design of MLGS-based nanocomposites.