Establishment of "in situ" Measurement Method for mass and Viscoelasticity Changes at Interfaces between Electrode and Solution

使用石英晶体电极的分析技术最适合于检查电极反应动力学。技术上可分为主动法和被动法。在被称为石英晶体微量天平（QCM）技术的主动方法中，使石英晶体自身自发地振荡，并且使用频率计数器对振荡频率进行计数。另一方面，在无源方法中，我们在此称之为石英晶体阻抗（QCI）方法，将交流电压施加到石英晶体上，并获得阻抗-频谱。本研究建立了这两种方法的现场测量系统。根据压电导纳测量，发现电等效电路参数（即，电阻R、电感L和电容C分量）可以被评估，并且意味着在氧化还原反应期间电极上的薄膜的质量、粘弹性和/或机械应力变化。建立了电极分离压电石英晶体等效电路参数和串联谐振频率的测量方法。结果表明，该装置可以成为检测液体性质变化的有力工具。

Analytical techniques using the quartz crystal electrodes are most suitable for examining the electrode reaction dynamics. The techniques can be divided into active method and passive method. In the active method, which is known as quartz crystal microbalance(QCM) technique, a quartz crystal itself is made to oscillate spontaneously and an oscillation frequency is counted using a frequency counter. On the other hand, in the passive method, which we call quartz crystal impedance(QCI) method herein, ac voltage is applied to a quartz crystal and an impedance-frequency spectrum is obtained. In this research, the in situ measurement systems of the both methods have been established. From the piezoelectric admittance measurements, it was found that the electrical equivalent circuit parameters(i.e., resistance R, inductance L and capacitance C components) on electrode surfaces can be evaluated and mean the mass, viscoelasticity and/or mechanical stress changes of thin films on electrodes during the redox reactions. The measurement method of the equivalent circuit parameters and the series resonant frequency of the electrode-separated piezoelectric quartz crystal was also established. It was demonstrated that this device can be a powerful tool for detecting changes in liquid properties.