Electrophoretic Motion of a Charge-Regulated Sphere Normal to a Plane

✍ Scribed by Yu-Po Tang; Ming-Hui Chih; Eric Lee; Jyh-Ping Hsu

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 83 KB
• Volume: 242
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.2001.7770

✦ Synopsis

The electrophoresis of a charge-regulated spherical particle normal to a planar surface is analyzed theoretically. The present study extends previous analyses in that the surface of the particle assumes a general charged condition, which simulates biocolloids and particles covered by an artificial membrane, and an arbitrary, double layer thickness κa, κ, and a being respectively the reciprocal Debye length and particle radius. We conclude that the thinner the double layer and/or the larger the particle-surface distance, the greater the mobility of the particle. If the concentration of the dissociable functional groups on particle surface N s is low, the absolute mobility of a particle decreases with the increase in κa, and the reverse is true if N s is high. For a medium N s , the absolute mobility has a local maximum as κa varies. We show that the higher the pH of the liquid phase, the smaller the absolute mobility.