Electro-osmosis
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In [[electrochemistry]], [[physics]] and [[vascular plant]] [[plant biology|biology]], '''electro-osmosis''', also called '''electroendosmosis''', is the motion of [[Chemical polarity|polar]] [[liquid]] through a [[artificial membrane|membrane]] or other porous structure (generally, along charged surfaces of any shape and also through non-macroporous materials which have ionic sites and allow for water uptake, the latter sometimes referred to as "chemical porosity" ) under the influence of an applied [[electric field]]. Electro-osmosis was first described by F.F. Reuss in [[1809]], and has growing applications in [[microfluidics]].
== Applications ==
=== Vascular plant biology ===
In vascular plant biology, electro-osmosis is also used as an alternative or supplemental explanation for the movement of polar liquids via the [[phloem]] that differs from the [[cohesion-tension theory]] supplied in the mass flow hypothesis and others, such as [[cytoplasmic streaming]]. <ref>Clegg, C.J., Mackean, D. G. (2006), p340-343</ref> Principally, [[companion cells]] are involved in the "cyclic" withdrawal of ions (<math>K^+</math>) from sieve tubes, and their secretion parallel to their position of withdrawal between sieve plates, resulting in polarisation of sieve plate elements alongside [[potential difference]] in pressure, and results in polar water molecules and other solutes present being moved upwards through the phloem. <ref>Clegg, C.J., Mackean, D. G. (2006), p340-343</ref><ref>V. V. Polevoi , T. E. Bilova1 and Yu. I. Shevtsov (2003)</ref>
In 2003, [[St Petersburg University]] graduates based an experiment on the electro-osmosis hypothesis through the application of direct [[electric current]] to 10mm segments of mesocotyls of maize seedlings alongside one-year linden shoots used with normal conducting systems and without vascular bundles; electrolyte solutions present in the tissues moved towards the cathode that was in place, suggesting that electro-osmosis may play a role in solution transport through conductive plant tissues. <ref>V. V. Polevoi, T. E. Bilova1 and Yu. I. Shevtsov (2003)</ref>
=== Physics ===
In [[fuel cell]]s, electro-osomosis causes [[proton]]s moving through a [[Proton Exchange Membrane|proton exchange membrane]] (PEM) to drag water molecules from one side ([[anode]]) to the other ([[cathode]]).
==See also==
*[[Capillary electrophoresis]]
*[[Electroosmotic flow]]
*[[Streaming current]]
*[[Zeta potential]]
== Notes ==
<references />
== References ==
# V. V. Polevoi , T. E. Bilova1 and Yu. I. Shevtsov (2003) "''Electroosmotic Phenomena in Plant Tissues ''" Biology Bulletin; Volume 30, Number 2
# Clegg, C.J., Mackean, D. G. (2006) "''Advanced Biology - principles & applications''" Hodder Stoughton Publhishers
[[Category:Electrochemistry]]
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