Electrophoresis of hydrophilic/hydrophobic rigid colloid with effects of relaxation and ion size. Issue 9 (12th February 2019)

• Record Type: Journal Article
• Authors: Kumar, Binod; Gopmandal, Partha P.; Sinha, R. K.; Ohshima, H.
• Is Part Of: Electrophoresis. Volume 40:Issue 9(2019)
• Page Start: 1282
• Page End: 1292
• Publication Date: 2019-02-12
• Subjects: Carnahan and Starling model -- Electrophoresis -- Ion size effect -- Slip length to Debye length ratio; Electrophoresis -- Periodicals; Electrophoresis -- Periodicals; 541.372
• DOI: 10.1002/elps.201800427
• Languages: English
• ISSNs: 0173-0835

Abstract

Abstract: This article deals with a semi‐analytical study on the electrophoresis of charged spherical rigid colloid by considering the effects of relaxation and ion size. The particle surface is taken to be either hydrophilic or hydrophobic in nature. In order to consider the ion size effect we have invoked the Carnahan and Starling model ( J. Chem. Phys . 1969, 51, 635‐636). The mathematical model is based on Stokes equation for fluid flow, modified Boltzmann equation for spatial distribution of ionic species and Poisson equation for electric potential. We adopt a linear perturbation technique under a weak electric field assumption. An iterative numerical technique in employed to solve the coupled set of perturbed equations. We have validated the numerically obtained electrophoretic mobility with the corresponding analytical solution derived under low potential limit. Going beyond the widely employed Debye‐Hückel linearization, we have presented the results for a wide range of surface charge density, electrolyte concentration, and slip length to Debye length ratio. We have also identified several interesting features including occurrence of local maxima and minima in the mobility for critical choice of pertinent parameters.