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Multiphysics Simulation of Ion Concentration Polarization Induced by a Surface-Patterned Nanoporous Membrane in Single Channel Devices
journal contribution
posted on 2014-10-21, 00:00 authored by Mingjie Jia, Taesung KimMicrofluidic devices utilize ion
concentration polarization (ICP)
phenomena for a variety of applications, but a comprehensive understanding
of the generation of ICP is still necessary. Recently, the emergence
of a novel single channel ICP (SC-ICP) device has stimulated further
research on the mechanism of ICP generation, so that we developed
a 2-D model of an SC-ICP device that integrates a nanoporous membrane
on the bottom surface of the channel, allowing bulk flow over the
membrane. We solved a set of coupled governing equations with appropriate
boundary conditions to explore ICP numerically. As a result, we not
only showed that the simulation results held a strong qualitative
agreement with experimental results, but also found the distribution
of ion concentrations in the SC-ICP device that has never been reported
in previous studies. We confirmed again that the electrophoretic mobility
(EPM) of counterions in the membrane is the most dominant factor determining
the generation and strength of ICP, whereas the charge density of
the membrane was dominant to the ICP strength only when a high EPM
value was assumed. From the viewpoint of practical applications, an
SC-ICP device with a long membrane under low buffer strength showed
enhanced performance in the preconcentration of charged molecules.
Therefore, we believe that the simulation results could not only provide
sharp insight into ICP phenomena but also predict and optimize the
performance of SC-ICP devices in various microfluidic applications.