title: Molecular dynamics simulation of electrokinetic flow of an aqueous electrolyte solution in nanochannels.
abstract: Electrokinetic flows of an aqueous NaCl solution in nanochannels with negatively charged surfaces are studied using molecular dynamics simulations. The four transport coefficients that characterize the response to weak electric and pressure fields, namely, the coefficients for the electrical current in response to the electric field (M(jj)) and the pressure field (M(jm)), and those for the mass flow in response to the same fields (M(mj) and M(mm)), are obtained in the linear regime using a Green-Kubo approach. Nonequilibrium simulations with explicit external fields are also carried out, and the current and mass flows are directly obtained. The two methods exhibit good agreement even for large external field strengths, and Onsager's reciprocal relation (M(jm) = M(mj)) is numerically confirmed in both approaches. The influence of the surface charge density on the flow is also considered. The values of the transport coefficients are found to be smaller for larger surface charge density, because the counter-ions strongly bound near the channel surface interfere with the charge and mass flows. A reversal of the streaming current and of the reciprocal electro-osmotic flow, with a change of sign of M(mj) due to the excess co-ions, takes places for very high surface charge density.
authors.affiliation: Toyota Central R&D Labs., Inc., Nagakute, Aichi 480-1192, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Laboratory for Interdisciplinary Physics, UMR 5588, Université Grenoble 1 and CNRS, 38402 Saint Martin d'Hères, France.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Mizuno
authors.affiliation: Toyota Central R&D Labs., Inc., Nagakute, Aichi 480-1192, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kinjo
authors.affiliation: Toyota Central R&D Labs., Inc., Nagakute, Aichi 480-1192, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Washizu
authors.affiliation: Laboratory for Interdisciplinary Physics, UMR 5588, Université Grenoble 1 and CNRS, 38402 Saint Martin d'Hères, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Barrat