Electrical currents and liquid flow rates in micro-reactors

Fletcher, Paul D.I., Haswell, Stephen J. and Zhang, Xunli (2001) Electrical currents and liquid flow rates in micro-reactors Lab on a Chip, 1, (2), pp. 115-121. (doi:10.1039/b106339c).

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For micro-reactor devices in which liquids are pumped by electro-osmotic flow (EOF), in situ monitoring of the electrical currents in the channel networks provides a valuable diagnostic tool. We demonstrate here that the voltage–current characteristics of a micro-reactor channel network can be accurately modelled using measurements of the full 3-D geometry of the channel network, the liquid conductivity and the channel wall–liquid surface conductivity. It is shown that surface conductivity provides a significant contribution to the overall measured electrical currents in channel networks for which the ratio of surface area to volume is high. Following correction for surface conductivity, the electrical currents are proportional to the liquid volumetric flow rates measured in the different branches of the channel network. The constant of proportionality is related to the zeta potential of the channel wall–liquid surface. Measurements of the variation of electrical currents and volumetric flow rates as a function of the applied voltages allows the determination of the surface conductivity and zeta potential within the micro-reactor which enables the prediction of the voltages required to produce the desired flow rates in any channel section. In situ logging of the electrical currents, incorporated within the control system, allows continuous monitoring of the liquid flow rates during micro-reactor operation.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1039/b106339c
ISSNs: 1473-0197 (print)
ePrint ID: 64835
Date :
Date Event
5 October 2001Published
Date Deposited: 16 Jan 2009
Last Modified: 16 Apr 2017 17:18
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/64835

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