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Transient ζ‐potential measurements in hydrophobic, TOPAS microfluidic substrates
Author(s) -
Tandon Vishal,
Bhagavatula Sharath K.,
Kirby Brian J.
Publication year - 2009
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200900028
Subject(s) - microfluidics , transient (computer programming) , materials science , nanotechnology , chromatography , biophysics , chemistry , biology , computer science , operating system
We utilize time‐resolved electrokinetic measurements in order to study the electrokinetic properties of silica and TOPAS microfluidic channels as a function of the time history of the fluid–solid interface. In pressure‐driven flow through TOPAS microchannels, the ζ‐potential as inferred from streaming potential measurements decays exponentially by a factor of 1.5 with a characteristic decay time of 3 h after the initial formation of the fluid–solid interface. A similar exponential decay is observed immediately after water is exchanged for ethanol as the solvent in the system. In electroosmotically driven flow through TOPAS microchannels, the ζ‐potential as inferred through current monitoring experiments was constant in time. No electrokinetic transients were observed in silica microchannels under these flow conditions.