21 research outputs found
Generic transport coefficients of a confined electrolyte solution
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. Using this
numerical scheme, the influence of the salt concentration on the transport
coefficients is investigated. Anomalous reversal of diffusio-osmotic current,
as well as that of electro-osmotic flow, is observed at high surface charge
densities and high added-salt concentrations.Comment: 6 pages with 6 figure