What does electroosmosis mean?
Electroosmosis is the movement of a liquid through a narrow channel, membrane, or porous material that results from an applied electric field. When a voltage is placed across such a material, the typically charged surfaces attract a thin layer of oppositely charged ions from the fluid; when this layer moves, it drags the surrounding liquid with it by viscous forces. The effect is exploited across science and engineering: it pumps fluids through tiny capillaries in laboratory analysis, helps dewater clays and remediate contaminated soils, and has been used to preserve timber and masonry by drawing moisture out of walls. The word derives from 'electro-' combined with Greek-derived 'osmosis', meaning impulse or thrust. Related forms include the adjective 'electroosmotic' and the synonymous terms 'electro-endosmosis' and 'electro-osmosis'. Though rarely heard outside technical settings, electroosmosis describes a real and increasingly useful phenomenon wherever liquids meet charged surfaces under voltage.
nounThe motion of a liquid through a porous material, membrane, or capillary caused by an applied electric field. It occurs because the charged walls of the pore attract a layer of counter-ions in the fluid, which then drag the bulk liquid along when a voltage is applied.
- The movement of liquid through a capillary, membrane, or porous solid induced by an applied electric field.
- (By extension) the use of this effect as a technique, as in soil remediation, dewatering, or microfluidic pumping.
"Electroosmosis drives groundwater toward the cathode, allowing contaminated soil to be dewatered and cleaned in place."
"In capillary electrophoresis, electroosmosis provides the pumping force that carries analytes down the tube."
"The team stabilized the landslide-prone slope by using electroosmosis to drain water from the clay."
Rarely used in the plural; the concept is almost always discussed as an uncountable phenomenon.
"Different electrolytes produced markedly different electroosmoses across the membranes tested."
Stick electrodes into wet soil and the water starts walking toward one of them — engineers use this trick to dry out mud without digging.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of electroosmosis
Electroosmosis combines the combining form 'electro-', from Greek 'ēlektron' (amber), with 'osmosis', from Greek 'ōsmos', meaning push or impulse. The phenomenon was first observed in experiments on charged capillaries in the early nineteenth century, and the term entered scientific English alongside related coinages such as 'osmosis' and 'electrophoresis'. Its cognates include 'osmotic' and 'osmoregulation', all tracing back to the same Greek root for thrusting or impulsion.
Related word forms
How electroosmosis is actually used
A technical term used chiefly in physics, chemistry, geotechnical engineering, and microfluidics; also commonly spelled 'electro-osmosis' or 'electro-endosmosis'. The adjective form is 'electroosmotic' (or 'electro-osmotic').
Easily confused with electroosmosis
Electrophoresis is the migration of charged particles or molecules through a fluid under an electric field, whereas electroosmosis is the movement of the fluid itself through a charged channel or porous medium.