Electrophoretic Motion of a Spherical Particle with a Symmetric Nonuniform Surface Charge Distribution in a Nanotube

• Published in: Langmuir Vol. 24; no. 10; pp. 5332 - 5340
• Main Authors: Qian, Shizhi, Joo, Sang W, Hou, Wen-Sheng, Zhao, Xuxin
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 20.05.2008
• Subjects: Algorithms; Biological Transport; Chemistry; Colloidal state and disperse state; Electrolytes; Electromagnetic Fields; Electrophoresis - methods; Exact sciences and technology; General and physical chemistry; Interfaces: Adsorption, Reactions, Films, Forces; Ions; Models, Statistical; Models, Theoretical; Motion; Nanotubes - chemistry; Osmosis; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Software; Static Electricity; Surface physical chemistry; Surface Properties; Motion; Electric potential; Surface charge; Electrolyte solution; Stokes equation; Nanoparticle; Theory; Fluid; Nanotube; Poisson equation; Hydrodynamics; Complexes; Velocity; Electric field; Electrolyte; Dynamics; Distribution; Electrophoresis; Spherical particle; Electrostatic force
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la703590p

The electrophoretic motion of a spherical nanoparticle, subject to an axial electric field in a nanotube filled with an electrolyte solution, has been investigated using a continuum theory, which consists 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. In particular, the effects of nonuniform surface charge distributions around the nanoparticle on its axial electrophoretic motion are examined with changes in the bulk electrolyte concentration and the surface charge of the tube’s wall. A particle with a nonuniform charge distribution is shown to induce a corresponding complex ionic concentration field, which in turn influences the electric field and the fluid motion surrounding the particle and thus its electrophoretic velocity. As a result, contrary to the relatively simple dynamics of a particle with a uniform surface charge, dominated by the irradiating electrostatic force, that with a nonuniform surface charge distribution shows various intriguing behaviors due to the additional interplay of the nonuniform electro-osmotic effects.