Contact angles: From past mistakes to new developments through liquid-solid adhesion measurements
Contact angles: From past mistakes to new developments through liquid-solid adhesion measurements
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DOI：
10.1016/j.cis.2019.02.002
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发表时间：
2019-05-01
影响因子：
15.6
通讯作者：
Drelich, Jaroslaw W.
中科院分区：
文献类型：
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作者：
Drelich, Jaroslaw W.
对于液-固体系观察到的接触角不一定是唯一的值，并且需要仔细考虑与液体铺展、粘附和相分离有关的几个不同的接触角。尽管接触角的概念很简单，并且经过了200多年的研究，但对实验接触角的解释仍然存在争议，错误也很常见。在这里，平衡接触角背后的物理原理被重申，并简要讨论了它们在现代文学中的误用。选定的进展，在20世纪世纪，形成目前的实验接触角的解释也严格审查和评估。在过去的二十年中，对液体在固体上的接触角的理解有所提高，并且这种进步是由先进的成像技术和接触角测量中的改进方法驱动的;通常与液体液滴与固体接触的直接力测量相结合。本实验室采用微电子天平系统测量了液滴的自发铺展力和液滴收缩、分离过程中不同阶段的水-固粘附力。配备有相机和数据采集软件的微量天平直接测量这些力，监测液滴表面分离，包括液滴拉伸的距离，并同时收集光学图像。这些图像用于根据测得的液滴尺寸、表面形状和接触角值来分析毛细管力和表面张力。这些力的测量，大大促进了我们的基本了解前进，后退和最稳定的接触角，以及它们与粘附力的相关性，并在此综述中进行了总结。(C)2019爱思唯尔B. V.保留所有权利。
A contact angle observed for a liquid-solid system is not necessarily a unique value and a few different contact angles need to be carefully considered in relation to liquid spreading, adhesion and phase separation. Despite the conceptual simplicity of the contact angle and over 200 years of investigation, interpretations of experimental contact angles remain controversial, and mistakes are quite common. Here, the physics behind equilibrium contact angles are restated and their misuse in modem literature is briefly discussed. Selected advances made in the 20th century that shaped current interpretations of experimental contact angles are also critically reviewed and evaluated. Understanding of contact angles for liquids on solids has improved in the last two decades and-this' progress is driven by advanced imaging techniques and improved methodologies in contact angle measurements; often in tandem with direct force measurements for liquid droplets in contact with solids. In our laboratory,,a microelectronic balance system is employed to measure the force of liquid droplet spontaneous spreading and the water-solid adhesion forces at different stages of droplet retraction and separation. A microbalance equipped with a camera and data acquisition software measures these forces directly, monitors droplet-surface separation including distances over which the droplet stretches, and collects optical images simultaneously. The images are used to analyze capillary and surface tension forces based on measured droplet dimensions, shapes of surfaces and values of contact angles. These force measurements have significantly furthered our fundamental understanding of advancing, receding and most stable contact angles, and their correlations with adhesion, and are summarized in this review. (C) 2019 Elsevier B.V. All rights reserved.