Ab initio nanofluidics: disentangling the role of the energy landscape and of density correlations on liquid/solid friction

Gabriele Tocci (1) , Maria Bilichenko (1) , Laurent Joly (2, 3) , Marcella Iannuzzi (1)

1 UZH - Universität Zürich [Zürich] = University of Zurich
2 iLM - MMCI - iLM - Modélisation de la matière condensée et des interfaces
3 IUF - Institut universitaire de France

Despite relevance to water purification and renewable energy conversion membranes, the molecular mechanisms underlying water slip are poorly understood. We disentangle the static and dynamical origin of water slippage on graphene, hBN and MoS₂ by means of large-scale ab initio molecular dynamics. Accounting for the role of the electronic structure of the interface is essential to determine that water slips five and eleven times faster on graphene compared to hBN and to MoS₂, respectively. Intricate changes in the water energy landscape as well as in the density correlations of the fluid provide, respectively, the main static and dynamical origin of water slippage. Surprisingly, the timescales of the density correlations are the same on graphene and hBN, whereas they are longer on MoS₂ and yield a 100% slowdown in the flow of water on this material. Our results pave the way for an in silico first principles design of materials with enhanced water slip, through the modification of properties connected not only to the structure, but also to the dynamics of the interface.

Mots clés: Nanoscale

Domaines: Sciences de l'ingénieur [physics]; Chimie; Physique [physics]

Gabriele Tocci, Maria Bilichenko, Laurent Joly, Marcella Iannuzzi. Ab initio nanofluidics: disentangling the role of the energy landscape and of density correlations on liquid/solid friction. Nanoscale, 2020, 12 (20), pp.10994-11000. ⟨10.1039/D0NR02511A⟩. ⟨hal-02869542⟩