Electrophoresis of electrically neutral porous spheres induced by selective affinity of ions

Abstract

We investigate the possibility that electrically neutral porous spheres electrophorese in electrolyte solutions with asymmetric affinity of ions to spheres on the basis of electrohydrodynamics and the Poisson-Boltzmann and Debye-Bueche-Brinkman theories. Assuming a weak electric field and ignoring the double-layer polarization, we obtain analytical expressions for electrostatic potential, electrophoretic mobility, and flow field. In the equilibrium state, the Galvani potential forms across the interface of the spheres. Under a weak electric field, the spheres show finite mobility with the same sign as the Galvani potential. When the radius of the spheres is significantly larger than the Debye and hydrodynamic screening length, the mobility monotonically increases with increasing salinity.

arXiv comment11pages, 6 figures

References in corpus (5)

• Induced-charge Electrokinetic Phenomena: Theory and Microfluidic Applications
• Induced-Charge Electro-Osmosis
• Solvation Effects in Near-Critical Binary Mixtures
• Precipitation in aqueous mixtures with addition of strongly hydrophilic or hydrophobic solute
• Effects of strongly selective additives on volume phase transition in gels

Cited by in corpus (2)

• Electrophoretic mobility of a water-in-oil droplet separately affected by the net charge and surface charge density
• Stokes drag on a sphere in a three-dimensional anisotropic porous medium