Eur. Phys. J. E (2015) 38: 127
https://doi.org/10.1140/epje/i2015-15127-y

Regular Article

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

¹ Institute of Computational Physics, University of Vienna, Sensengasse 8/9, 1090, Vienna, Austria
² Department of Physics and INFN, University of “Tor Vergata”, Via della Ricerca Scientifica 1, 00133, Rome, Italy
³ Istituto per le Applicazioni del Calcolo CNR, Via dei Taurini 19, 00185, Rome, Italy

^* e-mail: marcello.sega@univie.ac.at

Received: 20 July 2015
Accepted: 30 October 2015
Published online: 30 November 2015

Abstract

We investigate the slip properties of water confined in graphite-like nanochannels 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.