Optimising graphene exfoliation via numerical studies of particle-laden Taylor-Couette flow

In this study, a novel experimental rig is used to perform liquid phase exfoliation of graphite in order to produce graphene. This predominantly makes use of Taylor-Couette flow, with exfoliation taking place in the narrow gap between a stationary outer cylinder and rotating inner one. Numerical simulations of the flow with particles are performed, utilising a point particle approach, at a range of rotational speeds and particle sizes. This allows one to identify regions of high particle concentration and shear rates; regions where these coexist are where exfoliation is maximised. Our results suggest that larger particles migrate towards the outer cylinder wall preferentially, where shear rates are high due to the large velocity gradient in the near wall region. These results complement experimental studies, where utilisation of larger graphite flakes has generated higher graphene concentrations.