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

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 framework opens the way to explore the frequency-dependent FC for a wide range of complex liquids.

Automated summary

By establishing an analytical framework connecting the Navier friction coefficient with random force autocorrelation, the performance control issue of nanofluidic devices has been addressed. This generic framework also tackles problems related to frequency dependence and system size dependence of the FC.