title: Solvent-mediated nonelectrostatic ion-ion interactions predicting anomalies in electrophoresis.
abstract: We study the effects of solvent-mediated nonelectrostatic ion-ion interactions on electrophoretic mobility of a charged spherical particle. To this end, we consider the case of low surface electrostatic potential resulting in the linearization of the governing equations, which enables us to deduce a closed-form analytical solution to the electrophoretic mobility. We subsequently compare our results to the standard model using Henry's approach and report the changes brought about by the nonelectrostatic potential. The classical approach to determine the electrophoretic mobility underpredicts the particle velocity when compared with experiments. We show that this issue can be resolved by taking into account nonelectrostatic interactions. Our analysis further reveals the phenomenon of electrophoretic mobility reversal that has been experimentally observed in numerous previous studies.
authors.affiliation: Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India.
authors.forename: Prakash
authors.initials: P
authors.lastname: Goswami
authors.affiliation: Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India.
authors.forename: Jayabrata
authors.initials: J
authors.lastname: Dhar
authors.affiliation: Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India.
authors.forename: Uddipta
authors.initials: U
authors.lastname: Ghosh
authors.affiliation: Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India.
authors.forename: Suman
authors.initials: S
authors.lastname: Chakraborty
mesh_terms: D004586:Electrophoresis / Q000379:methods*; D007477:Ions / Q000737:chemistry*; D008962:Models, Theoretical; D009994:Osmolar Concentration; D010316:Particle Size; D012997:Solvents / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D007477:Ions; D012997:Solvents
keywords: Electrophoretic mobility reversal; Nonelectrostatic Yukawa interaction; Poisson-Helmholtz-Boltzmann equation