title: Effect of charged boundary on electrophoresis: Sphere in spherical cavity at arbitrary potential and double-layer thickness.
abstract: The boundary effect on electrophoresis is investigated by considering a spherical particle at an arbitrary position in a spherical cavity. Our previous analysis is extended to the case where the effect of double-layer polarization can be significant. Also, the effect of a charged boundary, which yields an electroosmotic flow and a pressure gradient, thereby making the problem under consideration more complicated, is investigated. The influences of the level of the surface potential, the thickness of double layer, the relative size of a sphere, and its position in a cavity on the electrophoretic behavior of the sphere are discussed. Some results that are of practical significance are observed. For example, if a positively charged sphere is placed in an uncharged cavity, its mobility may have a local minimum as the thickness of the double layer varies. If an uncharged sphere is placed in a positively charged cavity, the mobility may have a local minimum as the position of the sphere varies. Also, if the size of a sphere is fixed, its mobility may have a local minimum as the size of a cavity varies. These provide useful information for the design of an electrophoresis apparatus.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei, 10617 Taiwan.
authors.forename: Jyh-Ping
authors.initials: JP
authors.lastname: Hsu
authors.forename: Zheng-Syun
authors.initials: ZS
authors.lastname: Chen
authors.forename: Ming-Hong
authors.initials: MH
authors.lastname: Ku
authors.forename: Li-Hsien
authors.initials: LH
authors.lastname: Yeh
mesh_terms: D000465:Algorithms; D053841:Electroosmosis / Q000379:methods*; D004586:Electrophoresis / Q000379:methods*; D008962:Models, Theoretical