Electrokinetic potential - Electrokinetic potential

Japanese: 界面動電位 - かいめんどうでんい

…Since the system as a whole is electrically neutral, ions of the opposite charge to the particle charge surround the particle interface, forming an interfacial electric double layer. Because of the interfacial electric double layer, interfacial electrical phenomena such as electrophoresis, electroosmosis, streaming potential, and sedimentation potential are observed, but it is not the true charge of the particle interface that governs these behaviors, but the potential of the sliding surface where the relative motion of the particle and the medium occurs, which is called the zeta (ζ) potential or interfacial dynamic potential. When two particles with an electric double layer approach each other, in addition to the van der Waals force, which is the universal force acting between particles, an electrostatic repulsive force due to the interaction between the electric double layers acts, and the force acting between the particles is determined by the balance between these two forces. …

From [Electrophoresis]

...(2) Application to separation and analysis At the solid-liquid interface, a potential gradient occurs due to the rearrangement of charges. The potential difference that plays an important role when mechanically moving a liquid phase is the difference between the potential inside the liquid phase and the potential outside the Helmholtz layer (called the interfacial potential or zeta potential) (Figure), and by utilizing the difference in zeta potential, components can be separated and analyzed from a mixture of colloidal particles by electrophoresis. Therefore, it is applied to the purification, separation, and analysis of proteins, amino acids, pigments, etc. in fields such as colloid chemistry, biochemistry, medical chemistry, and immunochemistry. ...

*Some of the terminology that refers to "electrokinetic potential" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…系全体としては電気的中性が保たれるので，粒子界面の周辺には粒子電荷と反対符号のイオンがとりまき界面電気二重層をつくる。界面電気二重層のために，電気泳動，電気浸透，流動電位，沈降電位などの界面電気現象を示すが，これらの挙動を支配するのは粒子界面の真電荷ではなく，粒子と媒質の相対運動が生じるすべり面の電位であり，これをゼータ(ζ)電位または界面動電位という。電気二重層をもつ二つの粒子が接近すると，粒子間に働く普遍的な力であるファン･デル･ワールス力のほかに，電気二重層間の相互作用による静電的な反発力が働き，この2種の力のかね合いによって粒子間に働く力がきまる。…

【電気泳動】より

…(2)分離，分析への応用　固‐液界面においては電荷の再配列によって電位勾配が生じている。液相を機械的に動かすときに重要な役割を演ずる電位差は，液相の内部の電位とヘルムホルツ層の外側の電位との差(界面動電位またはζ電位と呼ぶ)であり(図)，ζ電位の差を利用すると電気泳動により，コロイド粒子の混合物から成分を分離，分析できる。したがってコロイド化学，生化学，医化学，免疫化学などの分野で，タンパク質，アミノ酸，色素などの精製，分離，分析に応用されている。…

※「界面動電位」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典第２版について | 情報

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