title: Influence of material transition and interfacial area changes on flow and concentration in electro-osmotic flows.
abstract: This paper presents a numerical study to investigate the effect of geometrical and material transition on the flow and progression of a sample plug in electrokinetic flows. Three cases were investigated: (a) effect of sudden cross-sectional area change (geometrical transition or mismatch) at the interface, (b) effect of only material transition (i.e. varying ζ-potential), and (c) effect of combined material transition and cross-sectional area change at the interface. The geometric transition was quantified based on the ratio of reduced flow area A2 at the mismatch plane to the original cross-sectional area A1. Multiple simulations were performed for varying degrees of area reduction i.e. 0-75% reduction in the available flow area, and the effect of dispersion on the sample plug was quantified by standard metrics. Simulations showed that a 13% combined material and geometrical transition can be tolerated without significant loss of sample resolution. A 6.54% reduction in the flow rates was found between 0% and 75% combined material and geometrical transition.
authors.affiliation: Department of Radiology, Washington University in St. Louis, St. Louis, MO 63110, USA. ranis@mir.wustl.edu
authors.forename: Sudheer D
authors.initials: SD
authors.lastname: Rani
authors.forename: Byoung-Hee
authors.initials: BH
authors.lastname: You
authors.forename: Steve A
authors.initials: SA
authors.lastname: Soper
authors.forename: Michael C
authors.initials: MC
authors.lastname: Murphy
authors.forename: Dimitris E
authors.initials: DE
authors.lastname: Nikitopoulos
mesh_terms: D055664:Electrochemical Techniques; D008422:Materials Testing; D044085:Microfluidics; D008954:Models, Biological; D009995:Osmosis; D011076:Polycarboxylate Cement / Q000737:chemistry; D016133:Polymerase Chain Reaction; D019904:Polymethyl Methacrylate / Q000737:chemistry
chemical_list: D011076:Polycarboxylate Cement; C005506:polycarbonate; D019904:Polymethyl Methacrylate