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dc.contributor.authorKhademi, Mahmoud
dc.contributor.authorBarz, Dominik P. J.
dc.date.accessioned2020-05-28T14:06:59Z
dc.date.available2020-05-28T14:06:59Z
dc.date.issued2019
dc.identifier.citationKhademi, M., & Barz, D. P. J. (2018). Dielectric relaxation spectroscopy of aqueous micellar electrolyte solutions: A novel application to infer Dukhin number and zeta potential of a micelle. ELECTROPHORESIS, 40(5), 710–719. doi:10.1002/elps.201800293en
dc.identifier.urihttp://hdl.handle.net/1974/27845
dc.description.abstractThe complex permittivities of aqueous SDS solutions, with and without the addition of sodium chloride (NaCl), are measured in the frequency range from 200 MHz to 14 GHz. The SDS concentrations are chosen such that the SDS molecules aggregate to micelles. In this frequency range, the measured spectra allow for the identification of two different relaxation processes. That is, the relaxation of the water molecules at frequencies above 1 GHz and the micellar relaxation at frequencies lower than 1 GHz. It is found that the addition of NaCl to the system mostly affects the micellar relaxation process. In detail, the time constant as well as the amplitude of the relaxation decrease by adding NaCl. These effects are attributed to the change in the solution conductivity that changes the properties of the micelle's electrical double layer. We also extract the Dukhin number of the micelles as a function of surfactant and electrolyte content from the measurements. The Dukhin number is a dimensionless group that describes the influence of the surface conductivity on a phenomena. A regression between Dukhin numbers and free sodium ions is found so that all data collapses on a single curve independent of the surfactant concentration. The surface conductivity is a manifestation of the electrical double layer and we use the Bikerman equation to infer the zeta potential of the micelles. Comparison to literature data shows very good agreement and proves that dielectric relaxation spectroscopy can be engaged to infer the zeta potential of micelles. Abbreviations: CMC critical micelle concentration, DRS dielectric relaxation spectroscopy, EDL electrical double layeren
dc.description.sponsorshipNatural Sciences and Engineering Research Council of Canadaen
dc.publisherWileyen
dc.rightsThis is the peer reviewed version of the following article: Khademi, M., & Barz, D. P. J. (2018). Dielectric relaxation spectroscopy of aqueous micellar electrolyte solutions: A novel application to infer Dukhin number and zeta potential of a micelle. ELECTROPHORESIS, 40(5), 710–719. doi:10.1002/elps.201800293, which has been published in final form at http://dx.doi.org/10.1002/elps.201800293. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.en
dc.subjectDielectric relaxation spectroscopyen
dc.subjectDukhin numberen
dc.subjectMicelleen
dc.subjectSurfactanten
dc.subjectZeta potentialen
dc.titleDielectric relaxation spectroscopy of aqueous micellar electrolyte solutions: A novel application to infer Dukhin number and zeta potential of a micelleen
dc.typejournal articleen
dc.identifier.doihttps://dx.doi.org/10.1002/elps.201800293


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