Study on surface electricity XXIII : Measurement of the electro-capillary maximum by U-Effect II

[Author abstract]If a glass capillary containing a mercury-salt solution interface, as shown in Fig. A, is forced to vibrate mechanically, an a-c voltage is generated between the two electrodes, a and b. The voltage has the same wave characler as the mechanical vibration.This is called by the author. The principle is more or less the same as in the case of the condenser microphone, since the electrical double layer at the mercury-solution interface behaves as a perfect condenser. However, the total double layer capacity changes periodically by virtue of the interfacial area change in the present case, while it is due to the change in the condenser gap distance in the case of the condenser microphone. The voltage of U-effect II (V) value is a function of the polarizing potential, when a DC potential Ep is applied to the mercury-solution ,interface in the glass capillary and was found to be equal to zero at the electrocapillary maximum (ecm). The wave form was observed by using the synchroscope and the Polaroid camera over the whole range of polarization. Even at the corona point, i.e. the anodic or cathodic polarizing potential which gives the maximum V-volts value, the wave form was sinusoidal. In accordance with the theoretical and experimental results reported here. We can therefore expect that the electro-capillary maximum can be obtained by measuring the V-voltage as a function of the polarization.[著者抄録]U効果IIによる電気毛管の極大(ecm)の研究水銀-電解質溶頼界面 (以下界面と言えばこの両者の界面をさす｡)を音波超音波又はmoving coil振動機で振動させると、加えた波形に等しい電圧が界面に生ずる。これを著者はU効果IIと命名した｡この現象は水銀-電解質溶液界面積が周期的に変化した時に、その界面電気二重相聞の周期的な充放電現象である｡我々の実験の結果U電圧は別の回路から界面に加えられた分極電圧Epの関数である。この事から電気毛管極大(ecm)の点でU電圧は零となる｡(U-Ep曲線と微分容量Cd-Ep曲線を比較する事によって、カチオンとアニオンがecm電圧の近くで平行を保つ様に見える。)即ち第5図の様にU電圧-分極電圧 (E)曲線が横軸を切る点がecmである｡同時に第6a図の様に此の点で U電圧の位相が反転するから一層ecmは求め安い。｡又我々は分極電圧 |E|でU電圧が急降下する点をコロナ点と呼んだ｡(界面が正弦振動の場合コロナ点ではU電圧は正弦波を示すが、 |E|値が上ってU値が殆んど零になると波形が乱れる此の点が放電点に相当する｡)一般に電解質溶液に、微温の界面活性剤の様な、有機物質を添加した場合のecm測定不可能の場合が多い｡その様な場合でも上記の様にU-E曲線を作ればecmの測定は簡単である。今回の報告でecmを測定した無機化合物はKF, Nacl, Kbr, Kl, Na_2SO_4, KNO_3, K2CO_3, etc.であり、有機化合物はt-amylalcohl, butyric acid, IM propionic acid(無関係イオンとして1N Na_2SO_4)である