Issue 13, 2017

Slip divergence of water flow in graphene nanochannels: the role of chirality

Abstract

Graphene has attracted considerable attention due to its characteristics as a 2D material and its fascinating properties, providing a potential building block for nanofabrication. In nanochannels the solid–liquid interface plays a non-negligible role in determining the fluid dynamics. Therefore, for an optimal design of nanofluidic devices, a comprehensive understanding of the slippage in a water flow confined between graphene walls is important. In nanoconfinement, experimental and computational studies have found the slip length to increase nonlinearly when the shear rate is larger than a critical value. Here, by conducting molecular dynamics simulations, we study the influence of the graphene crystallographic orientation on the slip boundary conditions inside a nanoslit channel. The flow in channels with heights of 2.0, 2.4 and 2.8 nm is driven parallel to the zig-zag and arm-chair crystallographic directions. We extract flow rates, velocity profiles, slip velocities and slip lengths. The slip velocity displays a linear relationship to the shear stress up to a critical value, which is not size dependent. Moreover, the slip length is found to be shear stress dependent above a critical shear stress value of 0.4 MPa. Furthermore, our results indicate that after this critical shear stress is reached, the flow rates are significantly influenced (up to 10%) by the particular orientation of the graphene topology.

Graphical abstract: Slip divergence of water flow in graphene nanochannels: the role of chirality

Supplementary files

Article information

Article type
Communication
Submitted
12 Nov 2016
Accepted
01 Feb 2017
First published
02 Feb 2017

Phys. Chem. Chem. Phys., 2017,19, 8646-8652

Slip divergence of water flow in graphene nanochannels: the role of chirality

E. Wagemann, E. Oyarzua, J. H. Walther and H. A. Zambrano, Phys. Chem. Chem. Phys., 2017, 19, 8646 DOI: 10.1039/C6CP07755B

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