Li Xiaojuan, Zhang Liqiang, Feng Yange, Zhang Youlin, Xu Haozhe, Zhou Feng, Wang Daoai
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Nano. 2023 Dec 12;17(23):23977-23988. doi: 10.1021/acsnano.3c08742. Epub 2023 Nov 27.
Visualizing the motion of water droplets and understanding their electrification behavior holds significance for applications related to droplet transport, self-cleaning, and anti-icing/deicing and for providing a comprehensive explanation of the solid-liquid triboelectrification mechanism. Here, by constructing microcolumnar structures on the polytetrafluoroethylene surface, a water droplet-based single electrode triboelectric nanogenerator was fabricated for visualizing charge dynamics when a water droplet bounces on a hydrophobic surface. The motion state of the water droplet is closely linked to its electrification behavior through the integration of a high-speed camera and an ammeter. The electrification behavior stemming from the bounce of the water droplet is dynamically captured in real-time. The results show that the magnitude and polarity of the electrical signal have strong dependence on the motion state of the water droplet. For instance, when a water droplet approaches or moves away from the substrate in a single direction, a unipolar electrical signal is generated. However, when the water droplet reaches its limit in the initial motion direction, it signifies a static equilibrium state, resulting in the electrical signal being at zero. Furthermore, we examine the impact of factors such as impact speed, drop contact area, contact line spreading/retraction speed, and impact angle on electrification. Finally, based on the close relationship between poly(ethylene oxide) (PEO) droplet bounce dynamics and electrical signals, the bouncing details of PEO droplets with different concentrations are tracked by electrical signals. This study digitally presents the whole process of droplet bounce in situ and provides a means for monitoring and tracking droplet movement.
可视化水滴的运动并了解其起电行为对于与水滴传输、自清洁、防冰/除冰相关的应用具有重要意义，并且有助于全面解释固液摩擦起电机理。在此，通过在聚四氟乙烯表面构建微柱状结构，制备了一种基于水滴的单电极摩擦纳米发电机，用于可视化水滴在疏水表面弹跳时的电荷动态。通过集成高速摄像机和电流表，水滴的运动状态与其起电行为紧密相连。实时动态捕捉水滴弹跳产生的起电行为。结果表明，电信号的大小和极性强烈依赖于水滴的运动状态。例如，当水滴沿单一方向靠近或远离基底时，会产生单极电信号。然而，当水滴在初始运动方向上达到极限时，这表示处于静态平衡状态，导致电信号为零。此外，我们研究了诸如撞击速度、液滴接触面积、接触线扩展/收缩速度和撞击角度等因素对起电的影响。最后，基于聚环氧乙烷（PEO）液滴弹跳动力学与电信号之间的密切关系，通过电信号跟踪不同浓度PEO液滴的弹跳细节。本研究以数字方式原位呈现了液滴弹跳的全过程，并提供了一种监测和跟踪液滴运动的方法。
