A study of electrochemical transport and diffuse charge dynamics in nanoscale devices using a Langevin equation

electrokinetics;Langevin equation;confined Stokes;Smooth Particle Mesh Ewald (SPME)

Ku, Da ; Saintillan ; David

关键词: electrokinetics;    Langevin equation;    confined Stokes;    Smooth Particle Mesh Ewald (SPME);   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/46644/Da_Ku.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

This thesis aims to develop new numerical and computational tools to study electrochemical transport and diffuse charge dynamics at small scales. Previous efforts at modeling electrokinetic phenomena at scales where non-continuum effects become significant have included continuum models based on the Poisson-Nernst-Planck equations and atomic simulations using molecular dynamics algorithms. Neither of them is easy to use or conducive to electrokinetic transport modeling in strong confinement or over long time scales. This work introduces a new approach based on a Langevin equation for diffuse charge dynamics in nanofluidic devices, which incorporates features from both continuum and atomistic methods. The model is then extended to include steric effects resulting from finite ion size, and applied to various phenomena involving charge dynamics between parallel-plate blocking electrodes. An efficient N log N algorithm for Stokes suspension simulations in doubly-periodic confined geometries is also developed, and applied to simulate electro-osmosis. Finally, the results of this approach are compared to those of the continuum model based on the Poisson-Nernst-Planck and Stokes equations.