Equilibrium and Transport Properties of Aqueous Electrolytes within Narrow Slit-Shaped Pores: from Molecular Dynamics Results to Nanofluidics Devices

摘要

We report equilibrium molecular dynamics simulation results for structural and dynamicrnproperties of aqueous electrolyte solutions confined within narrow pores. The slitshapedrnpores are carved from cristobalite silica. The pore width is in the range 0.8 – 1.0rnnm. The aqueous solutions contain NaCl and CsCl at 1M.rnEquilibrium simulations are performed at ambient conditions within the NVT ensemble.rnThe results are analyzed for both water and electrolytes in terms of density profilesrnaway from the solid substrates, self diffusion coefficients in the direction parallel to thernsolid substrate, and residence time at contact with the solid substrate.rnThe data suggest the formation of layered structures. Because the self-diffusionrncoefficient is faster as the distance from the solid increases, the ions that are at the porerncenter diffuse more quickly through the pore than those adsorbed closer to the wall.rnThus our results could be used to design membranes to separate, e.g., aqueous NaClrnfrom CsCl solutions.