The flow and rheology of graphene: modelling to predict the `unseen’
Fluids and Materials Seminar
6th May 2021, 2:00 pm – 3:00 pm
Online seminar, Zoom link is sent to the fluids and materials seminar mailing list on Mondays.
Graphene nanoparticles are ubiquitous, used in everything from drug delivery to electronics. Made from just a few atomic layers, the instantaneous dynamics of these plate-like particles in flowing liquids are, experimentally, practically inaccessible. We study theoretically and computationally the flow dynamics and rheology of dilute suspensions of graphene in a simple shear flow field. In the infinite Péclet number limit, a rigid platelet with the interfacial surface slip properties of graphene does not follow the periodic rotations predicted for classical colloidal particles but aligns itself at a small inclination angle with respect to the flow. This unexpected result is due to the surface slip reducing the tangential stress at the graphene-solvent surface. By analysing the Fokker-Plank equation for the orientational distribution function for decreasing Péclet numbers, we explore how surface slip affects the flow and rheology of graphene suspensions. We find that surface slip can dramatically change the macroscopic behaviour of the suspension. For example, the effective viscosity of a dilute suspension of graphene platelets is predicted to drop significantly for typical slip length values.