A New Analytical Formulation for the Electrophoretic Mobility of a Colloidal Sphere

Journal Article (2025)
Author(s)

Angela Casarella (Chalmers University of Technology)

Simon Gourdin-Bertin (Independent researcher)

C. Chassagne (TU Delft - Environmental Fluid Mechanics)

Environmental Fluid Mechanics
DOI related publication
https://doi.org/10.3390/e27040336
More Info
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Publication Year
2025
Language
English
Environmental Fluid Mechanics
Issue number
4
Volume number
27
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Abstract

A new analytical equation for the electrophoretic mobility of a colloidal sphere, homogeneously charged, is derived. This equation reduces to the well-known Henryโ€™s formulation for low surface potentials. For high surface potentials, the equation is compared to the full numerical result. It is found that the equation performs well up to surface potentials of 50 mV. For larger surface potentials, the equation performs well for ๐œ…๐‘Ž>10, where ๐œ… is the inverse of Debyeโ€™ s length and a the radius of the particle. Differences between analytical and numerical solutions for ๐œ…๐‘Ž<10 are studied. The case of a particle with a constant surface charge is discussed. In that case, a very simple equation relates the surface charge of the particle to the electrophoretic mobility for ๐œ…๐‘Ž>10.