Colloidal electro-phoresis in the presence of symmetric and asymmetric electro-osmotic flow. Issue 40 (27th September 2018)

• Record Type: Journal Article
• Authors: Botin, Denis; Wenzl, Jennifer; Niu, Ran; Palberg, Thomas
• Is Part Of: Soft matter. Volume 14:Issue 40(2018)
• Page Start: 8191
• Page End: 8204
• Publication Date: 2018-09-27
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c8sm00934a
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : We conduct simultaneous measurements of the electro-phoretic and electro-osmotic velocities in case of symmetric and asymmetric solvent flows. Abstract : We characterize the electro-phoretic motion of charged sphere suspensions in the presence of substantial electro-osmotic flow using a recently introduced small angle super-heterodyne dynamic light scattering instrument (ISASH-LDV). Operation in integral mode gives access to the particle velocity distribution over the complete cell cross-section. Obtained Doppler spectra are evaluated for electro-phoretic mobility, wall electro-osmotic mobility and particle diffusion coefficient. Simultaneous measurements of differing electro-osmotic mobilities leading to asymmetric solvent flow are demonstrated in a custom made electro-kinetic cell fitting standard microscopy slides as exchangeable sidewalls. The scope and range of our approach are discussed demonstrating the possibility of an internal calibration standard and using the simultaneously measured electro-kinetic mobilities in the interpretation of a microfluidic pumping experiment involving an inhomogeneous electric field and a complex solvent flow pattern.