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(1) Presentation(s)

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Mar. 23/10/2018 10:00 Salle RdC, Bâtiment 11, RdC

Séminaire
CUI Jin (University of Twente)
J. Cui, prof. dr. S. G. Lemay, MESA+ Institute for Nanotechnology, University of Twente PO Box 217, 7500 AE Enschede, The Netherlands
Mass Transport in Electrochemical Nanofluidic Devices

Sommaire:

Nanogaps consist of a pair of separately addressable electrodes defining the floor and the roof of a <100 nm high channel and provide amplification of faradaic signals via efficient redox cycling. Mass transport in these devices exhibits several properties which are not encountered in conventional configurations. First, even weak molecule-surface interactions can have significant impact due to the high surface-to-volume ratio inherent to the nanochannel geometry. This leads to hindered diffusion and can adversely affect the response time for detection at low flow rates, but can also in principle be exploited for separating species advected along the channel. Second, the ability to locally control the ratio of reduced-to-oxidized species via electrode potentials, coupled with the differences in diffusion coefficients exhibited by the majority of redox couples, can cause spatially varying analyte concentrations along a channel. This in turn leads to counter-intuitive behavior such as the potential at a downstream electrode influencing the response of an upstream detector. While nanogaps provide an ideal tool for studying these effects which are otherwise difficult to observe directly, we expect that the behavior is general and also occurs in other systems where electrochemical conversion takes place in confined fluidic geometries


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