Molecular dynamics simulation of high slip flow of water confined between graphene nanochannels at experimentally accessible strain rates

TL;DR

This study uses the transient time correlation function (TTCF) method to accurately evaluate water slip behavior between graphene nanochannels at shear rates accessible in experiments, overcoming limitations of traditional molecular dynamics.

Contribution

First application of TTCF to compute slip length and friction coefficient in high-slip water-graphene systems at experimentally relevant shear rates.

Findings

TTCF results agree with previous equilibrium simulations and experiments.

TTCF effectively probes high-slip systems at low shear rates.

NEMD results at accessible shear rates are obtained using TTCF.

Abstract

The transient time correlation function method (TTCF) has emerged as a powerful methodology for accurately probing systems at low shear rates. In the present study, TTCF was used to evaluate the shear rate dependence of the slip length in a high-slip system consisting of water confined between graphene walls at experimentally accessible shear rates, for which classical nonequilibrium molecular dynamics (NEMD) is unfeasible. The corresponding Navier friction coefficient was computed for all shear rates spanning six orders of magnitude and compared with the equilibrium limit. We report for the first time NEMD results obtained at experimentally accessible shear rates using the TTCF approach for a system that has attracted significant interest over the past decades. The slip length calculated with TTCF is in good agreement with previous equilibrium molecular dynamics simulations and experiments. Our aim here is to highlight the extraordinary power of TTCF, particularly for high-slip (low strain-rate) systems, and to verify that equilibrium methods directly match NEMD measurements at experimentally accessible strain rates.