Generic transport coefficients of a confined electrolyte solution

Hiroaki Yoshida (1) , Hideyuki Mizuno (2) , Tomoyuki Kinjo , Hitoshi Washizu , Jean-Louis Barrat (3)

1 Molecular Fluid Dynamics Sub-department, Fluid Engineering and Science Division
2 LIPhy - Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères]
3 PSM

Physical parameters characterising electrokinetic transport in a confined electrolyte solution are reconstructed from the generic transport coefficients obtained within the classical non-equilibrium statistical thermodynamic framework. The electro-osmotic flow, the diffusio-osmotic flow, the osmotic current, as well as the pressure-driven Poiseuille-type flow, the electric conduction, and the ion diffusion, are described by this set of transport coefficients. The reconstruction is demonstrated for an aqueous NaCl solution between two parallel charged surfaces with a nanoscale gap, by using the molecular dynamic (MD) simulations. A Green-Kubo approach is employed to evaluate the transport coefficients in the linear-response regime, and the fluxes induced by the pressure, electric, and chemical potential fields are compared with the results of non-equilibrium MD simulations. Anomalous reversal of diffusio-osmotic current, as well as that of electro-osmotic flow, at high surface charge density and high added-salt concentration is also discussed.

Domaines: Matière Molle [cond-mat.soft]; Chimie-Physique [physics.chem-ph]; Dynamique des Fluides [physics.flu-dyn]

Hiroaki Yoshida, Hideyuki Mizuno, Tomoyuki Kinjo, Hitoshi Washizu, Jean-Louis Barrat. Generic transport coefficients of a confined electrolyte solution. 2014. ⟨hal-01067859⟩