subject: Zeta Potential - Property Of An Electric Structure That Is Usually Built Up At Interfaces [print this page]
Zeta potential is a parameter characterizing electrochemical balance on connections. It relies on the qualities of fluid as well as on qualities of the outer lining area. It performs an important part theoretically of aggregative balance - DLVO concept [1,2]. Electrostatic repulsion between contaminants relies on the value of zeta prospective. The higher the zeta prospective, the more powerful the repulsion, the more constant the system becomes. For instance, high zeta prospective of the fat drops in dairy stops them against coalescence. Reduction of it due to addition of acid would lead to dairy products development from coalescence drops.
Zeta prospective is a property of a powered framework that is usually built up at interfaces: Dual Part. According to Basic principles of Colloid and Program Science by J. Lyklema [3]: "...the reason for the development of a "relaxed" ("equilibrium") double layer is the non-electric appreciation of charge-determining ions for a surface...". This process leads to the build up of an "electric surface charge". This surface cost makes an electrostatic area that then impacts the ions in the large of the fluid. This electrostatic area, along with the heat motion of the ions, makes a countercharge, and thus displays the electrical powered surface cost. The net power cost in this testing soften layer is equal in scale to the net surface cost, but has the opposite polarity. As a result the complete framework is electronically fairly neutral.
Electric potential decays almost exponentially, which allows introduction "Debye length" as estimate of the DL thickness. Electric potential drops by approximately 2.7 times at the distance from the surface that equals to the Debye length. Debye length depends mostly on an "ionic strength". It is approximately 1 nm at the ionic strength 0.1 M, and it increases as a reciprocal square root of the ionic strength (electrolyte concentration), becoming, for instance, 10 nm at the ionic strength 0.001 M.
There is another characteristic distance within DL - location of a "slipping plane" associated with tangential motion of the liquid relative to the surface. Liquid underneath of the slipping plane remains attached to the surface. Electric potential corresponding to the slipping plane is " Zeta potential ". It is measured in mV and cannot exceed 100 mV.
Author:
Dispersion Technology, Inc. was established in 1996 by Philip Goetz, its Chairman and Dr. Andrei DukhinScientific instrumentation for heterogeneous system characterization is a major business area. DTI has developed and is currently marketing a family of instruments based on ultrasound for characterizing particle size distribution, zeta potential, rheology, solid content, porosity, in concentrated dispersions such as CMP slurries, nano-dispersions, ceramic slurries, battery slurries, cements, pharmaceutical emulsions, etc, and in porous bodies.
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