Unidirectional Wetting Surfaces Fabricated by Ultrasonic-Assisted Cutting
Unidirectional Wetting Surfaces Fabricated by Ultrasonic-Assisted Cutting
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DOI：
10.20965/ijat.2019.p0191
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
K. Shimada;T. Hirai;M. Mizutani;T. Kuriyagawa
中科院分区：
文献类型：
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作者：
K. Shimada;T. Hirai;M. Mizutani;T. Kuriyagawa
表面微结构可以提供各种功能，并且润湿性是可以通过表面纹理控制的典型表面性质。单向润湿性能（UWP）作为工业功能的有用润湿功能已经获得关注。因此，在这项研究中，开发UWP使用表面微观结构进行了测试。首先，通过接触角（CA）的热力学分析计算UWP。分析结果表明，微结构倾斜角ω2的增大会使前进CA增大，而后退CA则无法计算，可能表现出钉扎效应。超声辅助切割随后被用来制造分层微结构，以提供UWP工件。虽然在结构的边缘上已经观察到许多倾斜，但是在设计的尺度中制备了具有不同倾斜角度（ω2=5 °、10°和15°）的微结构。最后，通过测量CA和滑动角（SA）来验证UWP。在不同的斜角结构中，CA滞后表现出各向异性，当ω2=10 °和15°时，SA的各向异性得到了证实。随后用两种不同的方法估算了液滴的保持力比r，这表明了UWP，并且两种方法在ω2=10 °至15°范围内得出了相似的r值。
Surface microstructures can provide various functionalities, and wettability is a typical surface property that can be controlled by surface textures. Unidirectional wetting properties (UWPs) have been garnering attention as a useful wetting function for industrial functions. Thus, in this study, developing UWPs using surface microstructures has been tested. First, UWPs were calculated with the thermodynamic analysis of contact angle (CA). The analytical results predicted that an increased oblique angle of the microstructures, ω2, can increase the advancing CA; the receding CAs could not be calculated, and might exhibit the pinning effect. Ultrasonic-assisted cutting was subsequently employed to fabricate hierarchical microstructures for providing UWPs to a workpiece. Although many burrs have been observed on the edges of the structures, microstructures with different oblique angles, ω2=5◦, 10°, and 15°, were fabricated in the designed scales. Finally, the UWPs were verified by measuring the CAs and sliding angles (SAs). The anisotropy of CA hysteresis was indicated in each oblique angle structure, and the anisotropy of SAs was confirmed when ω2=10◦and 15°. The retention force ratio of a droplet,r, which indicates the UWPs, was subsequently estimated with two different approaches, and both approaches led a similar value of the attrition rates ofrfrom ω2=10◦to 15°.