As a charged particle moves through a gravitational force or centrifugation, an electric potential is induced. While the particle moves, ions in the electric double layer lag behind creating a net dipole moment behind due to liquid flow. The sum of all dipoles on the particle is what causes sedimentation potential. Sedimentation potential has the opposite effect compared to electrophoresis where an electric field is applied to the system. Ionic conductivity is often referred to when dealing with sedimentation potential.
The following relation provides a measure of the sedimentation potential due to the settling of charged spheres. First discovered by Smoluchowski in 1903 and 1921. This relationship only holds true for non-overlapping electric double layers and for dilute suspensions. In 1954, Booth proved that this idea held true for Pyrex glass powder settling in a KCl solution. From this relation, the sedimentation potential, E, is independent of the particle radius and that E → 0, Φ  → 0 (a single particle).
Smoluchowski's sedimentation potential is defined where ε is the permitivity of free space, D the dimensionless dielectric constant, ξ the zeta potential, g the acceleration due to gravity, Φ the particle volume fraction, ρ the particle density, ρ the medium density, λ the specific volume conductivity, and η the viscosity.
Smoluchowski developed the equation under five assumptions:
# Particles are spherical, nonconducting, and monodispersed.
# Laminar flow around the particles occurs (Reynolds number <1).
# Interparticle interactions are negligible.
# Surface conduction is negligible.
# The double-layer thickness 1/κ is small compared to the particle radius a (κa>>1).
Where D is the diffusion coefficient of the ith solute species, and n is the number concentration of electrolyte solution.
Ohshimas model was developed in 1984 and was originally used to analyze the sedimentation velocity of a single charged sphere and the sedimentation potential of a dilute suspension. The model provided below holds true for dilute suspensions of low zeta potential, i.e. e'ζ/κT ≤2