Theoretical framework for the atomistic modeling of frequency-dependent liquid-solid friction

TL;DR

This paper develops a comprehensive analytical framework linking atomistic simulation data to frequency-dependent liquid-solid friction, addressing longstanding issues and enabling exploration of complex liquids' frictional behavior.

Contribution

It introduces a generic analytical method to determine frequency-dependent Navier friction coefficients from atomistic simulations, including system size and non-Markovian effects.

Findings

Addresses the long-standing plateau issue in friction coefficient evaluation.

Demonstrates non-Markovian behavior of liquid-solid friction in various liquids.

Framework applicable to complex liquids and different temperature regimes.

Abstract

Nanofluidics shows great promise for energy conversion and desalination applications. The performance of nanofluidic devices is controlled by liquid-solid friction, quantified by the Navier friction coefficient (FC). Despite decades of research, there is no well-established generic framework to determine the frequency dependent Navier FC from atomistic simulations. Here, we have derived analytical expressions to connect the Navier FC to the random force autocorrelation on the confining wall, from the observation that the random force autocorrelation can be related to the hydrodynamic boundary condition, where the Navier FC appears. The analytical framework is generic in the sense that it explicitly includes the system size dependence and also the frequency dependence of the FC, which enabled us to address (i) the long-standing plateau issue in the evaluation of the FC and (ii) the non-Markovian behavior of liquid-solid friction of a Lennard-Jones liquid and of water on various walls and at various temperatures, including the supercooled regime. This new framework opens the way to explore the frequency dependent FC for a wide range of complex liquids.