Study on growth mechanism of thin films during electrodepostion at two-liquid interface by measuring interfacial tension

到目前为止，这项研究的主要投资者和同事观察到两种不混溶液体之间界面处薄膜的二维生长。他们将界面应用于电化学制备薄膜。然而，它还没有澄清为什么薄膜生长优先在界面方向。我们试图阐明两种不互溶液体之间的界面处的薄膜的生长机制。在这项研究中，我们集中在薄膜电沉积过程中的界面张力的变化。首先，我们用Whilhelmy法测定了电沉积锌膜过程中醋酸丁酯与ZnSO_4之间的界面张力。结果，我们证实了在薄膜的生长前沿周围界面张力降低，这表明这种降低可以引起沿着界面的Marangoni对流，这可以产生Zn ^<2 +>到薄膜的生长前沿的快速传输。为了证实Marangoni对流在电沉积过程中的界面处的演化，我们应用纹影法和Mach-Zehnder干涉法观察薄膜电沉积过程中界面周围液体的运动。其结果是，我们可视化的漩涡的电解质在附近的生长前沿的膜。我们认为这个漩涡是由马兰戈尼对流引起的。最后，我们尝试了应用ripplon光散射技术测量两种不互溶液体之间的界面张力。我们研制了一套测量系统，并成功地测量了水和乙醇的表面张力。然而，我们不能得到足够强的ripplon强度来估计液体之间的界面张力。因此，我们需要改进系统，以获得良好的信号，通过ripplon。

So far the head investor of this study and coworkers observed two dimensional growth of a thin film at the interface between two immiscible liquids. They applied the interface to prepare thin films electrochemically. However, it has not yet clarified why the films grow preferentially in the interfacial direction. We tried to elucidate growth mechanism of the films at the interface between two immiscible liquids. In this study we focused on the change in interfacial tension during electrodeposition of thin films. First, we applied Whilhelmy method to measure the interfacial tension during electrodeposition of zinc films at the interface between n-butyl acetate and ZnSO_4. As a result, we confirmed that the interfacial tension decreased around the growth front of the film, suggesting that this decrease can induce Marangoni convection along the interface, which can generate rapid transportation of Zn^<2+> to a growth front of the film. In order to confirm evolution of Marangoni convection at the interface during electrodeposition, we applied Schlieren method and Mach-Zehnder interferometry to observe the motion of liquids around the interface during the electrodeposition of a thin film. As a result, we visualized vortex of the electrolyte in the vicinity of growth front of the film. We believe that this vortex is caused by Marangoni convection. Finally, we tried to apply ripplon light scattering technique to measure interfacial tension between two immiscible liquids. We made a system for the measurement, and succeeded in measure surface tensions of water and ethyl alcohol. However, we could not get strong intensity of ripplon enough to estimate interfacial tension between the liquids. Therefore, we need to improve the system to get good signals by ripplon.