Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/89027
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dc.contributor.authorLim, Chun Yeeen
dc.contributor.authorLim, An Engen
dc.contributor.authorLam, Yee Cheongen
dc.date.accessioned2018-05-18T08:41:48Zen
dc.date.accessioned2019-12-06T17:16:14Z-
dc.date.available2018-05-18T08:41:48Zen
dc.date.available2019-12-06T17:16:14Z-
dc.date.copyright2017en
dc.date.issued2017en
dc.identifier.citationLim, C. Y., Lim, A. E., & Lam, Y. C. (2017). pH Change in Electroosmotic Flow Hysteresis. Analytical Chemistry, 89(17), 9394–9399.en
dc.identifier.issn0003-2700en
dc.identifier.urihttps://hdl.handle.net/10356/89027-
dc.identifier.urihttp://hdl.handle.net/10220/44842en
dc.description.abstractElectroosmotic flow (EOF) or electro-osmosis has been shown to exhibit a hysteresis effect under displacement flow involving two solutions with different concentrations, i.e. the flow velocity for a high-concentration solution displacing a low-concentration solution is faster than the flow velocity in the reverse direction involving the same solution pair. On the basis of our recent numerical analysis, a pH change initiated at the interface between the two solutions has been hypothesized as the cause for the observed anomalies. We report the first experimental evidence of EOF hysteresis induced by a pH change in the bulk solution. pH-sensitive dye was employed to quantify the pH changes in the microchannel during EOF. The electric-field gradient across the boundary of two solutions generates an accumulation or depletion of a minority of pH-governing ions such as hydronium (H3O+) ions, thus inducing pH variations across the microchannel. When a high-concentration solution displaced a lower-concentration solution, a pH increase was observed, while the flow in the reverse direction induced a decrease in pH. This effect causes significant changes to the zeta potential and flow velocity. The experimental results show good quantitative agreement with numerical simulations. This work presents the experimental proof which validates the hypothesis of a pH change during electroomostic flow hysteresis as predicted by numerical analysis. The understanding of pH changes during EOF is crucial for accurate flow manipulation in microfluidic devices and maintenance of constant pH in biological and chemical systems under an electric field.en
dc.description.sponsorshipASTAR (Agency for Sci., Tech. and Research, S’pore)en
dc.format.extent14 p.en
dc.language.isoenen
dc.relation.ispartofseriesAnalytical Chemistryen
dc.rights© 2017 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by Analytical Chemistry, American Chemical Society. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1021/acs.analchem.7b02219].en
dc.subjectHysteresisen
dc.subjectElectroosmotic Flowen
dc.titlepH change in electroosmotic flow hysteresisen
dc.typeJournal Articleen
dc.contributor.schoolSchool of Mechanical and Aerospace Engineeringen
dc.identifier.doi10.1021/acs.analchem.7b02219en
dc.description.versionAccepted versionen
dc.identifier.rims207778en
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item.grantfulltextopen-
Appears in Collections:MAE Journal Articles
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