Assessing micro- and nanoscale adhesion via liquid metal-based contact angle measurements in vacuum
Assessing micro- and nanoscale adhesion via liquid metal-based contact angle measurements in vacuum
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DOI：
10.1007/s10853-019-04253-6
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发表时间：
2019-12-01
影响因子：
4.5
通讯作者：
Fatikow, Sergej
中科院分区：
文献类型：
--
作者：
von Kleist-Retzow, Fabian;Klauser, Waldemar;Fatikow, Sergej
了解润湿现象对于表面科学理论和应用的各个领域以及微纳机电系统的功能至关重要。接触角测量是一种公认的评估表面润湿性的方法。然而，当它应用于微纳米尺度结构时，面临着重大的挑战。在这里，我们利用液态金属合金的优越特性来测量接触角，从而创建了一种方法，可以在个位数微米及以下的小尺寸表面截面上可靠地检查润湿现象。该技术应用电迁移技术在真空环境下制备直径小于10微米的无氧化物金属液滴，使扫描电子显微镜能够用于接触角测量。静态和动态接触角的测量可以通过有针对性地操纵液滴来实现。展示了具有不同纳米级表面结构的微尺度表面截面的表征。采用这种方法，可以在小尺度上对润湿特性进行独特的表征。因此，所提出的方法对于各种新兴研究领域，如微纳米机器人以及微纳米尺度上的少量粗糙接触力学的研究具有重要意义。
Understanding wetting phenomena is of critical importance for various fields in theoretical and applied surface sciences as well as for the functionality of micro- and nanoelectromechanical systems. Contact angle measurement is one of the well-established methodologies for the wettability assessment of a surface. However, it faces major challenges when applied to micro- and nanoscale structures. Here, we exploit the superior properties of liquid metal alloys to contact angle measurement thus creating a methodology that allows for reliable examination of wetting phenomena on small-scale surface sections within the single-digit micrometer range and below. The technique applies electromigration to prepare oxide-free liquid metal droplets with diameters of less than ten micrometers in a vacuum environment, enabling a scanning electron microscope to be used for contact angle measurement. Static and dynamic contact angle measurements can be realized via the targeted manipulation of the droplets. The characterization of microscale surface sections with different nanoscale surface texture is demonstrated. Following this approach, unique characterization of wetting properties on the small scale becomes feasible. The methodology presented is therefore of significant importance for various emerging research fields such as micro- and nanorobotics as well as studies of few asperity contact mechanics on the micro- and nanoscale.