Please use this identifier to cite or link to this item:
Full metadata record
DC FieldValueLanguage
dc.contributor.authorLim, Chun Yeeen
dc.contributor.authorLim, An Engen
dc.contributor.authorLam, Yee Cheongen
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.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.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: [].en
dc.subjectElectroosmotic Flowen
dc.titlepH change in electroosmotic flow hysteresisen
dc.typeJournal Articleen
dc.contributor.schoolSchool of Mechanical and Aerospace Engineeringen
dc.description.versionAccepted versionen
item.fulltextWith Fulltext-
Appears in Collections:MAE Journal Articles
Files in This Item:
File Description SizeFormat 
pH Change in Electroosmotic Flow Hysteresis.pdf1.23 MBAdobe PDFThumbnail

Google ScholarTM



Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.