Zeta potential is a scientific term for electrokinetic potential in colloidal systems. In the colloidal chemistry literature, it is usually denoted using the Greek letter zeta, hence ζ-potential. From a theoretical viewpoint, zeta potential is electric potential in the interfacial double layer (DL) at the location of the slipping plane versus a point in the bulk fluid away from the interface. In other words, zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle.
A value of 25 mV (positive or negative) can be taken as the arbitrary value that separates low-charged surfaces from highly-charged surfaces.
The significance of zeta potential is that its value can be related to the stability of colloidal dispersions (e.g., a multivitamin syrup). The zeta potential indicates the degree of repulsion between adjacent, similarly charged particles (the vitamins) in a dispersion. For molecules and particles that are small enough, a high zeta potential will confer stability, i.e., the solution or dispersion will resist aggregation. When the potential is low, attraction exceeds repulsion and the dispersion will break and flocculate. So, colloids with high zeta potential (negative or positive) are electrically stabilized while colloids with low zeta potentials tend to coagulate or flocculate as outlined in the table.
|Zeta potential||Stability behavior of the colloid|
|from 0 to ±5,||Rapid coagulation or flocculation|
|from ±10 to ±30||Incipient instability|
|from ±30 to ±40||Moderate stability|
|from ±40 to ±60||Good stability|
|more than ±61||Excellent stability|
Zeta potential is widely used for quantification of the magnitude of the electrical charge at the double layer. However, zeta potential is not equal to the Stern potential or electric surface potential in the double layer. Such assumptions of equality should be applied with caution. Nevertheless, zeta potential is often the only available path for characterization of double-layer properties. Zeta potential should not be confused with electrode potential or electrochemical potential (because electrochemical reactions are generally not involved in the development of zeta potential).
Other articles related to "zeta potential, potential, zeta":
... The most known and widely-used theory for calculating zeta potential from experimental data is that developed by Marian Smoluchowski in 1903 ... rigorous electrokinetic theories that are valid for any zeta potential and often any κa, stem mostly from the Ukrainian (Dukhin, Shilov and others) and Australian (O'Brien, White, Hunter and others) schools ...
... Another induced change is an alteration in the zeta potential - an electrochemical property of cell surfaces that is determined by the net electrical charge of molecules exposed at the surface of cell membranes - of ... The normal zeta potential of the erythrocyte is -15.7 millivolts (mV) ... Much of this potential appears to be contributed by the exposed sialic acid residues in the membrane their removal results in zeta potential of -6.06 mV ...
... Zeta potential titration is a titration of heterogeneous systems, such as colloids, emulsions, etc ... type of titration is used to study the zeta potential of these surfaces under different conditions ...
... In a zeta-potential titration, the Zeta potential is the indicator ... Measurement of the zeta potential can be performed using microelectrophoresis, or electrophoretic light scattering, or electroacoustic phenomena ...
... When both electrodes are held at the same potential, the streaming current is measured directly as the electric current flowing through the electrodes ... can be left floating, allowing a streaming potential to build up between the two ends of the channel ... A streaming potential is defined as positive when the electric potential is higher on the high pressure end of the flow system that on the low pressure end ...
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