Measurement of electrocapillarity

Fundamental knowledge about the behavior of charged surfaces comes from experiments with mercury. How can an electrocapillarity curve of mercury be measured A usual arrangement, the so-called dropping mercury electrode, is shown in Fig. 5.2 [70], A capillary filled with mercury and a counter electrode are placed into an electrolyte solution. A voltage is applied between both. The surface tension of mercury is determined by the maximum bubble pressure method. Mercury is thereby pressed into the electrolyte solution under constant pressure P. The number of drops per unit time is measured as a function of the applied voltage. 

There are different methods of measuring the electrocapillarity of solid metals. In one method the deflection of a cantilever spring, which is coated on one side with the metal, is measured [71,72], The surface tension of the metallic side changes when the applied voltage 

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