On Applicability of Poisson-Boltzmann Equation for Micro-and Nanoscale Electroosmotic Flows

作     者：Moran Wang Shiyi Chen 

作者机构：Nanomaterials in EnvironmentAgriculture and Technology(NEAT)University of CaliforniaDavisCA 95616USA/Department of Mechanical EngineeringJohns Hopkins UniversityBaltimoreMD 21218USA. Department of Mechanical EngineeringJohns Hopkins UniversityBaltimoreMD 21218USA/College of EngineeringPeking UniversityBeijingChina 

出 版 物：《Communications in Computational Physics》 (计算物理通讯（英文）)

年 卷 期：2008年第3卷第5期

页      面：1087-1099页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：the grant from NSF-061308 

主　　题：Poisson-Boltzmann model electroosmotic flow EDL interaction Poisson-NernstPlanck equation. 

摘      要：The applicability of the Poisson-Boltzmann model for micro-and nanoscale electroosmotic flows is a very important theoretical and engineering *** this contribution we investigate this problem at two aspects:first the high ionic concentration effect on the Boltzmann distribution assumption in the diffusion layer is studied by comparisons with the molecular dynamics(MD)simulation results;then the electrical double layer(EDL)interaction effect caused by low ionic concentrations in small channels is discussed by comparing with the dynamic model described by the coupled Poisson-Nernst-Planck(PNP)and Navier-Stokes(NS)*** results show that the Poisson-Boltzmann(PB)model is applicable in a very wide range:(i)the PB model can still provide good predictions of the ions density profiles up to a very high ionic concentration(∼1 M)in the diffusion layer;(ii)the PB model predicts the net charge density accurately as long as the EDL thickness is smaller than the channel width and then overrates the net charge density profile as the EDL thickness increasing,and the predicted electric potential profile is still very accurate up to a very strong EDL interaction(λ/W∼10).