Water transport through a graphene channel with different cross-sectional shapes

Graphene is a multifunctional two-dimensional material that has attracted more and more attention in the scientific community, including novel nanofluidic devices. Since the graphene channel size can be tunable by experiments, our understanding on the effect of channel shape becomes urgent. In this work, we use molecular dynamics simulations to study the transport of pressure-driven water through gra-phene channels, by changing the cross-sectional shape while holding the area or volume constant. A key observation is that when the channel shape changes from two-dimensional to three-dimensional, the water flux increases monotonously because of the reduction in water translocation time, in consistent with the calculation by Navier-Stokes equation. The water flux in a square graphene channel will be slightly smaller than the carbon nanotube with similar volume. Meanwhile, in both two-and three-dimensional channels the water flux exhibits an excellent linear increase with the pressure difference that also agrees with the Navier-Stokes equation; while the translocation time displays a power law behavior, yielding to the Langevin dynamics. These results enrich our understanding of the influence of channel shape on water transport, which has far-reaching significance for the design of nanofluidic devices.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the influence of channel shape on water transport through graphene channels using molecular dynamics simulations. The results show that the water flux increases monotonously when the channel shape changes from two-dimensional to three-dimensional, due to the reduction in water translocation time, and this is consistent with the calculation by the Navier-Stokes equation.