Analysis of Self-Electrophoretic Motion of a Spherical Particle in a Nanotube: Effect of Nonuniform Surface Charge Density

Document Type

Article

Publication Date

2008

Publication Title

Langmuir

Volume

24

Issue

9

First page number:

4778

Last page number:

4784

Abstract

Autonomous motions of a spherical nanoparticle in a nanotube filled with an electrolyte solution were investigated using a continuum theory, which consisted of the Nernst−Planck equations for the ionic concentrations, the Poisson equation for the electric potential in the solution, and the Stokes equation for the hydrodynamic field. Contrary to the usual electrophoresis, in which an external electric field is imposed to direct the motion of charged particles, the autonomous motion originates from the self-generated electric field due to the ionic concentration polarization of the liquid medium surrounding an asymmetrically charged particle. In addition to the particle motion, the interaction between the electric field generated and the free charges of the polarized solution induces electroosmotic flows. These autonomous motions of the fluid as well as the particle were examined with focus on the effects of the surface−charge distribution of the particle, the size of the nanotube, and the thickness of the electric double layer, which affected the direction and the speed of the particle significantly.

Keywords

Electric fields; Electro-osmosis; Electrodynamics; Electrolyte solutions; Electrophoresis; Ion flow dynamics; Microfluidics; Nanoparticles; Nanotubes

Disciplines

Chemical Engineering | Chemistry | Electrical and Computer Engineering | Fluid Dynamics | Mechanical Engineering | Nanoscience and Nanotechnology

Language

English

Permissions

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