Kinetic study of surfactant-free graphene exfoliation at a solvent interface

The kinetics of graphite exfoliation at a liquid-liquid interface is investigated by monitoring the increase in graphene surface area as a function of time. With only two basic assumptions, we establish a kinetic model inspired by bacteria reproduction that describes the exfoliation process of graphite to graphene. The exfoliation process is spontaneous and is driven by the spreading of graphene at a liquid-liquid interface lowering the free energy of the system. While the thermodynamics of this process are understood, the kinetics have remained elusive. Understanding the exfoliation process of pristine, unfunctionalized graphene is important for potential applications of graphene that require a scalable approach to its production. Previous kinetic studies of graphite exfoliation are rare and are either computational results or are based on systems requiring the application of mechanical energy to drive exfoliation. We find our experimental data closely fits our kinetic model and allows for the determination of rate constants and activation energies for several grades of pristine natural flake graphite exfoliation. [Display omitted]