Breakdown of Fast Water Transport in Graphene Oxides

TL;DR

This paper investigates the conditions under which rapid water flow in graphene oxide nanoconfinements occurs, revealing that chemical functionalization and structural relaxation diminish the flow enhancement previously observed.

Contribution

It demonstrates through simulations that water flow enhancement breaks down in graphene oxides due to chemical and structural factors, emphasizing the need for boundary condition corrections.

Findings

Flow enhancement breaks down with chemical functionalization

Hydrodynamics applies at nanometer scales in graphene oxides

Corrections to slip boundary conditions are necessary for accurate modeling

Abstract

Fast slip flow was reported for water inside the interlayer gallery between graphene layers or carbon nanotubes. We report here that this flow rate enhancement (over two orders) breaks down with the presence of chemical functionalization and relaxation of the nanoconfinement in graphene oxides. Molecular dynamics simulation results show that hydrodynamics applies in this circumstance, even at length scales down to nanometers. However, corrections on the slip boundary condition and viscosity of nanoconfined flow must be included to make quantitative predictions. These results were discussed with structural characteristics of the liquid water and hydrogen bond networks.