The importance of chemical potential in the determination of water slip in nanochannels

TL;DR

This study uses molecular dynamics simulations to show that chemical potential critically influences water slip length in nanochannels, revealing that similar contact angles do not guarantee identical slip behavior without matching chemical potentials.

Contribution

It demonstrates the essential role of chemical potential in determining water slip length in nanochannels, highlighting the need to consider it alongside surface properties.

Findings

Chemical potential significantly affects water slip length.

Matching chemical potentials aligns slip lengths despite different surface potentials.

Methodological considerations are important for comparative analysis in confined systems.

Abstract

We investigate the slip properties of water confined in graphite-like nano-channels by non-equilibrium molecular dynamics simulations, with the aim of identifying and analyze separately the influence of different physical quantities on the slip length. In a system under confinement but connected to a reservoir of fluid, the chemical potential is the natural control parameter: we show that two nanochannels characterized by the same macroscopic contact angle -- but a different microscopic surface potential -- do not exhibit the same slip length unless the chemical potential of water in the two channels is matched. Some methodological issues related to the preparation of samples for the comparative analysis in confined geometries are also discussed.