STUDY OF NANOSCALE PRESSURE-DRIVEN ELECTROKINETIC FLOW WITH EFFECTS OF WALL LATTICE PLANE

摘要

The objective of the present study is to explore pressure-driven flows with the presence of electric double layer (EDL) in nanochannels of various wall lattice planes, Three face-centered cubic (fcc) lattice planes, i.e. fcc(111), fcc(100), and fcc(110), of the channel wall are considered. The structure of diffuse EDL and electrokinetic flow characteristics are dealt with in an atomistic view. Fluid and charge density layering phenomena and their influences on the Stern layer are investigated with the molecular dynamic simulation results. In most of the simulations, a monatomic molecule, W, is used as the solvent model and the charged particles W~+ and W~-of the same size as the ions. To examine behaviors of the dissimilar particles, a simulation with the aqueous model W for fluid, Na~+ for cation and Cl~- for anion is also performed. Effects of ion concentrations, wall-fluid interaction energy, and surface charge density on the electro-hydrodynamics are studied. In addition, based on the continuum theory, two analytic expressions for zeta potential with the presence of fluid slippage are derived and analyzed. The present results disclose interesting physics about the influences of wall lattice-fluid interactions, which are significant in further understanding and applications of the nanoscale electrokinetic flows.