Application of the Cathode-Ray Oscilloscope to Polarographic Phenomena. II. Surface Charge Density of the Electrical Double Layer.

Cathode-Ray Oscilloscopic Investigation of Phenomena at Polarizable Mercury Electrodes.

“…The values of Q can be obtained by graphical integration (30) of known capacity values. By electronic integration of the differential capacity-potential relation, oscillograms for surface charge density may be observed in a few seconds or less (60).…”

“…Further integration of equation 27 leads to an expression of surface tension vs. potential or the so-called electrocapillary curve. By performing a double electronic integration of the differential capacity-potential relation, it is possible to observe the electrocapillary curve (60).…”

“…The resulting oscillogram was an i-E pattern occurring 60 times each second. Reproducible traces were obtained by synchronizing the mercury drops with the frequency of the applied voltage, i.e., 60 drops per second. The practicability of using such short drop-times is questionable from the viewpoint of stirring effects.…”

“…Oscillograms of differential capacity current may be electronically integrated to give oscillographic patterns of surface charge density (60). The accuracy obtainable by this method is good when values of surface charge density obtained are compared to those from graphical integration of differential capacity values (31).…”

“…Ei = -0.336 v.; Ei = -1.305 v. on the shape of the electrocapillary curve were observed by Gouy (26,27) at an early date. However, such effects are more adequately studied by means of the curve for the differential capacity current or that for the surface charge density (59,60), since any small change in the electrocapillary or surface-tension curve is accentuated in the curves which are its first and second derivatives.…”