Strain Engineering Water Transport in Graphene Nano-channels

TL;DR

This study demonstrates that applying strain to graphene nano-channels significantly alters water transport by changing interfacial friction, offering a new method to control flow in nanofluidic devices.

Contribution

It introduces strain engineering as a novel approach to modulate water transport in graphene nano-channels, supported by molecular dynamics simulations.

Findings

Interfacial friction stress changes sixfold with strain from -10% to 10%.

Stretching increases shear stress; compression decreases it.

Molecular structure analysis reveals key roles of potential energy barriers and structural commensurateness.

Abstract

Using equilibrium and non-equilibrium molecular dynamic (MD) simulations, we found that engineering the strain on the graphene planes forming a channel can drastically change the interfacial friction of water transport through it. There is a sixfold change of interfacial friction stress when the strain changes from -10% to 10%. Stretching the graphene walls increases the interfacial shear stress, while compressing the graphene walls reduces it. Detailed analysis of the molecular structure reveals the essential roles of the interfacial potential energy barrier and the structural commensurateness between the solid walls and the first water layer. Our results suggest that the strain engineering is an effective way of controlling the water transport inside nano-channels. The resulting quantitative relations between shear stress and slip velocity and the understanding of the molecular mechanisms will be invaluable in designing graphene nano-channel devices.