Water transport properties versus temperature: classical and ab initio molecular dynamics simulations

Liquid water is ubiquitous in our everyday life and in industrial applications. It is also a complex liquid with many anomalies. In particular, the dynamics of supercooled liquid water at low temperature has attracted a lot of... [ view full abstract ]

Liquid water is ubiquitous in our everyday life and in industrial applications. It is also a complex liquid with many anomalies. In particular, the dynamics of supercooled liquid water at low temperature has attracted a lot of attention recently. Yet very few numerical works considered the hydrodynamic behavior of supercooled water, and wether this behavior is also anomalous as compared to other liquids. Here I will illustrate with recent work how molecular dynamics simulations can be used to predict and understand the bulk viscosity and interfacial friction coefficient of low temperature liquid water. I will first present an investigation of the viscosity and structural relaxation times of supercooled water using molecular dynamics with the TIP4P/2005f force field. We showed that this force field described accurately the viscosity and self-diffusion of water over a large range of temperatures, and we observed a decoupling between viscosity and the so-called alpha-relaxation time in supercooled water [1]. Using the same system, we then assessed the validity of elastic models (relating the viscous dynamics of supercooled liquids at long times to their elastic properties at short times) to describe supercooled water [2]. I will also present recent results on hydrodynamic slip of water on hydrophobic surfaces at low temperature [3]. In particular we observed and explained a strong increase of the slip length - quantifying the amplitude of slip - in the supercooled domain. Finally I will briefly describe our efforts to evaluate the accuracy of density functional theory to describe liquid water at different temperatures, focusing in particular on its dynamics quantified by both the diffusion coefficient and the shear viscosity [4].

[1] E. Guillaud, S. Merabia, D. de Ligny, L. Joly: "Decoupling of viscosity and relaxation processes in supercooled water: a molecular dynamics study with the TIP4P/2005f model", PCCP 19, 2124 (2017)
[2] E. Guillaud, L. Joly, D. de Ligny, S. Merabia: "Assessment of elastic models in supercooled water: a molecular dynamics study with the TIP4P/2005f force field", submitted
[3] E. Guillaud, S. Merabia, D. de Ligny, L. Joly, in preparation
[4] E. Guillaud, D. de Ligny, L. Joly, in preparation