Effect of hydrodynamic slip on the electrophoresis of hydrophobic spherical particles in a solution of general electrolytes.

This article deals with the electrophoresis of a charged hydrophobic spherical rigid colloid in the extent of general electrolyte. To show the impact of electrolyte ions of the background aqueous medium on the overall electrophoretic transport of hydrophobic colloids, we have considered various electrolyte solutions, including 1:1, 2:2, 3:3, 2:1, 3:1, 1:2 and 1:3 electrolytes as well as a mixed solution of 1:1 and 2:1 electrolytes. The surface ζ -potential is varied from low to sufficiently high. Considering the impact of relaxation effect, a general expression for electrophoretic mobility of the undertaken hydrophobic rigid colloid is derived, which is applicable for any value of the surface potential and at large κ a ( κ a ≥ ca. 30), where κ - 1 is the Debye layer thickness and a is the radius of the particle. We have further deduced various simple and useful approximate analytic mobility expressions for each type of the background aqueous solutions considering several electrostatic and hydrodynamic conditions. We have further illustrated the computational results to show the impact of hydrodynamic slip and choices of background electrolyte on the electrophoretic mobility, occurrence of maximum mobility at the critical choice of surface potential and the limiting mobility of sufficiently charged rigid colloids. [ABSTRACT FROM AUTHOR]