DSpace DSpace UPC
 Català   Castellano   English  

E-prints UPC >
Altres >
Enviament des de DRAC >

Empreu aquest identificador per citar o enllaçar aquest ítem: http://hdl.handle.net/2117/13524

Ítem no disponible en accés obert per política de l'editorial

Arxiu Descripció MidaFormat
Langmuir 201354s.pdf1,19 MBAdobe PDF Accés restringit

Citació: Yaroshchuk, A. [et al.]. Coupled concentration polarization and electroosmotic circulation near micro/nanointerfaces: Taylor-Aris model of hydrodynamic dispersion and limits of its applicability. "Langmuir", 20 Setembre 2011, vol. 27, núm. 18, p. 11710-11721.
Títol: Coupled concentration polarization and electroosmotic circulation near micro/nanointerfaces: Taylor-Aris model of hydrodynamic dispersion and limits of its applicability
Autor: Yaroshchuk, Andriy Veure Producció científica UPC; Zholkovskiy, Emiliy; Pogodin, Sergey; Baulin, Vladimir
Data: 20-set-2011
Tipus de document: Article
Resum: Mismatches in electrokinetic properties between micro- and nanochannels give rise to superposition of electroosmotic and pressure-driven flows in the microchannels. Parabolic or similar flow profiles are known to cause the so-called hydrodynamic dispersion, which under certain conditions can be formally assimilated to an increase in the solute diffusivity (Taylor-Aris model). It is demonstrated theoretically that taking into account these phenomena modifies considerably the pattern of current-induced concentration polarization of micro/nanointerfaces as compared to the classical model of unstirred boundary layer. In particular, the hydrodynamic dispersion leads to disappearance of limiting current. At essentially "over-limiting" current densities, the time-dependent profiles of salt concentration in microchannels behave like sharp concentration "fronts" moving away from the interface until they reach the reservoir end of the microchannel. Under galvanostatic conditions postulated in this study, these "fronts" move with practically constant speed directly proportional to the current density. The sharp transition from a low-concentration to a high-concentration zone can be useful for the analyte preconcentration via stacking. The pattern of moving sharp concentration "fronts" has been predicted for the first time for relatively broad microchannels with negligible surface conductance. The Taylor-Aris approach to the description of hydrodynamic dispersion is quantitatively applicable only to the analysis of sufficiently "slow" processes (as compared to the characteristic time of diffusion relaxation in the transversal direction). A posteriori estimates reveal that the condition of "slow" processes is typically not satisfied close to current-polarized micro/nanointerfaces. Accordingly, to make the description quantitative, one needs to go beyond the Taylor-Aris approximation, which will be attempted in future studies. It is argued that doing so would make even stronger the dampening impact of hydrodynamic dispersion on the current-induced concentration polarization of micro/nanointerfaces.
ISSN: 0743-7463
URI: http://hdl.handle.net/2117/13524
DOI: 10.1021/la201354s
Apareix a les col·leccions:Altres. Enviament des de DRAC
Departament d'Enginyeria Química. Articles de revista

Stats Mostra les estadístiques d'aquest ítem

SFX Query

Tots els drets reservats. Aquesta obra està protegida pels drets de propietat intel·lectual i industrial corresponents. Sense perjudici de les exempcions legals existents, queda prohibida la seva reproducció, distribució, comunicació pública o transformació sense l'autorització del titular dels drets.

Per a qualsevol ús que se'n vulgui fer no previst a la llei, dirigiu-vos a: sepi.bupc@upc.edu


Valid XHTML 1.0! Programari DSpace Copyright © 2002-2004 MIT and Hewlett-Packard Comentaris
Universitat Politècnica de Catalunya. Servei de Biblioteques, Publicacions i Arxius