Diffusiophoresis of a Spheroid at an Arbitrary xial Position in a Spherical Cavity
Date Issued
2009
Date
2009
Author(s)
Shih, I-Chung
Abstract
The boundary effect on the diffusiophoretic behavior of a spheroid is analyzed theoretically by considering the diffusiophoresis of a charged spheroid under arbitrary surface potential and double-layer thickness at an arbitrary position in an uncharged spherical cavity. We demonstrate that the phenomenon under consideration is governed by scaled surface potential, the aspect ratio of a spheroid, double-layer relaxation, chemiosmotic/diffusioosmotic flow, and two types of the competing double-layer polarization. Based on the assumption that the applied concentration gradient is weaker than the electric field and concentration field established by the particle and/or the boundary, we solve this phenomenon by virtue of the perturbation theory and the superposition principle. The scaled diffusiophoretic velocity are examined rank as prolate >sphere>oblate in general cases. The diffusiophoretic velocity as a function of the scaled surface potential, or the thickness of EDL, or the axial deviation, or the cavity size may exhibit a local maximum just because the competition of electric force and hydrodynamic drag determines the moving direction of the particle. These contributed to valuable information for the design and implementation of an diffusiophoresis operation.
Subjects
Diffusiophoresis
Boundary effect
Spheroid in spherical cavity
Double-layer polarization
Diffusioosmotic flow
Type
thesis
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