Lippmann capillary electrometer

See also -> adhesion, -> Dupre equation, -> Lippmann equation, -> Lippmann capillary electrometer, -> point of zero charge, -> Young equation. 

See also - electrocapillarity, - electrocapillary curve, -r Gibbs-Lippmann equation, - Wilhelmy plate (slide) method, - ring method, - Lippmann capillary electrometer. 

Electrocapillarity — (a) as a branch of science, this term covers all phenomena related to the thermodynamics of charged - interfaces, esp. of metal-solution interfaces. The term is practically synonymous with -> capillarity, but emphasizes the electric aspects, (b) The term electrocapillarity is often used in a restricted sense to mean the study of the equilibrium properties of metal solution interfaces, such as the - interfacial tension of mercury solution interfaces, the height of a mercury column (in the case of the - Lippmann capillary electrometer), or the -> drop time (in the case of the - dropping mercury electrode). More generally, however, the equilibrium properties of many other interfaces fall... 

Mar. 22,1874 Semily, then Austro-Hungarian Empire -Apr. 16, 1921, Prague, Czechoslovakia) Since 1912, Professor of experimental physics at Charles University, Prague. Kucera introduced the measurement of surface tension of polarized mercury by applying the dropping mercury electrode [i] rather than the Lippmann capillary electrometer, and he inspired thereby -> Heyrovsky, J. to introduce - polarography. 

Lippmann capillary electrometer — Figure 1. Lippmann capillary electrometer [ii]. For explanation see text... 

Lippmann capillary electrometer — Figure 2. (a), (b), (c) from left to right Lippmann capillary electrometers. (Reproduced (a) from [iii], and (b) and (c) from [iv]). For explanation see text and sources... 

This equation was first derived by Lippmann in the course of his studies that led him to develop the Lippmann capillary electrometer [i]. 

Ring method — Method to determine the - interfacial tension in liquid-gas systems introduced by Lecomte du Noiiy [i]. It is based on measuring the force to detach a ring or loop of a wire from the surface of a liquid. The method is similar to the -> Wilhelmyplate method when used in the detachment mode [ii]. See also -> electrocapillarity, -r electrocapillary curve, -> Gibbs-Lippmann equation, - Wilhelmy plate (slide) method, - drop weight method, - Lippmann capillary electrometer. 

Gibbs-Lippmann equation, drop weight method, -> ring method, Lippmann capillary electrometer, -> Wilhelmy. 

For practical reasons the capillary rise technique is rarely used for the measurement of interfacial (rather than surface) tensions large amounts of the two liquids are needed and there are suitable and convenient alternatives. An exception to this is the measurement of the Interfacial tension between mercury and (mostly) aqueous solutions at various potential differences applied across the liquid-liquid interface. Such measurements are done in a so-called Lippmann capillary electrometer, already described in the chapter on electric double layers (fig. 11.3.47). 

In 1887 Ostwald published a paper in which he showed that with the help of a dropping mercury electrode it is possible to measure the potential difference between a metal and a solution of electro-lyte (13). He describes his use of the dropping mercury electrode and the Lippmann capillary electrometer, giving some experimental details and numerous tables of data. He clearly points out the low accuracy of the method based on the measurement of the surface tension of mercury, noting that it appears to be fundamentally sound but that near the maximum value of the surface tension there is only a very small change of surface tension for a relatively large change of electromotive force. This measurement problem inherent in the Ostwald electrode potential was one of the points attacked by Nernst. 

See also capillarity, adhesion, double layer, Dupre equation, Gibbs-Lippmann equation, electrocapillary equation, -> electrokinetic effects, Lipp-mann equation, Lippmann capillary electrometer, point of zero charge, Young equation, Wilhelmy... 

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