Abstract

Nanofluidic systems, e.g. natural nanoporous materials or engineered nanochannels made from new 2D materials, could provide alternative solutions to critical societal challenges such as water desalination or energy harvesting. At the nanoscale, surface effects become crucial; in particular, liquid-solid slip arising from low liquid-solid friction can boost the performance of nanofluidic systems. In that context, I will illustrate with some recent work how molecular dynamics simulations can help understand the molecular mechanisms of liquid-solid friction, and optimize liquid-solid slip.

First, I will briefly discuss some recent progress regarding the molecular modeling of interfacial slip and friction [1], and show how ab initio molecular dynamics can provide a new insight into the structural and dynamical origin of liquid-solid friction [2]. Then, I will discuss a challenge related to nanofluidic systems for electricity production: optimal performance indeed requires charged and slipping surfaces, while these two properties are contradictory. Here we have shown that the charge-friction relationship strongly depends on how the surface charge is generated, and identified promising candidates for optimal charge-friction coupling [3]. Finally, I will show that water slip can be boosted when the liquid is “supercooled”, and investigate the origin of this unexpected effect [4].

References

[1] H. Oga, T. Omori, C. Herrero, S. Merabia, L. Joly, Y. Yamaguchi: “Theoretical framework for the atomistic modeling of frequency-dependent liquid-solid friction”, Phys. Rev. Research 3, L032019 (2021)

[2] G. Tocci, M. Bilichenko, L. Joly, M. Iannuzzi: “Ab initio Nanofluidics: Disentangling the role of the energy landscape and of density correlations on liquid/solid friction”, Nanoscale 12, 10994 (2020)

[3] Y. Xie, L. Fu, T. Niehaus, L. Joly: “Liquid-solid slip on charged walls: the dramatic impact of charge distribution”, Phys. Rev. Lett. 125, 014501 (2020)

[4] C. Herrero, G. Tocci, S. Merabia, L. Joly: “Fast Increase of Nanofluidic Slip in Supercooled Water: the Key Role of Dynamics”, Nanoscale 12, 20396 (2020)