Prediction of the molecular-level critical shear rates for the liquid exfoliation of graphene layers

Abstract

Liquid exfoliation is essential for enhancing the production of graphene with outstanding properties, and it is achieved by applying relevant shear force to graphene layers. This study predicted the critical shear rates required for the liquid exfoliation of different sizes of graphene with various layer numbers using molecular dynamics simulation. The simulations for the shear flow conditions were performed using the TIP4P water model, and the results were constrained using the SHAKE algorithm. In addition, the graphene layers and their van der Waals forces were modeled using Morse potentials. This enabled the accurate capturing of the differences between the shear rates in graphene layers and those in water molecules by simulation. Furthermore, the peeling and sliding exfoliation modes of graphene with varying layer numbers were extensively discussed.