A simple way to achieve pattern-dependent tunable adhesion in superhydrophobic surfaces by a femtosecond laser.
A simple way to achieve pattern-dependent tunable adhesion in superhydrophobic surfaces by a femtosecond laser.
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DOI：
10.1021/am3012388
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发表时间：
2012-08
影响因子：
9.5
通讯作者：
Dongshi Zhang;Feng Chen;Qing Yang;Jiale Yong;H. Bian;Yan Ou;J. Si;Xiangwei Meng;X. Hou
中科院分区：
文献类型：
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作者：
Dongshi Zhang;Feng Chen;Qing Yang;Jiale Yong;H. Bian;Yan Ou;J. Si;Xiangwei Meng;X. Hou
在本文中，我们提出了一种新的方法，由周期性的疏水图案和超疏水结构的飞秒（fs）激光照射硅可调粘附超疏水表面。表面由周期性疏水图案（三角形，圆形和菱形）和超疏水结构（由飞秒激光诱导的双尺度尖峰）组成。我们的研究结果表明，所制备的表面的粘附力可以通过改变超疏水结构域的面积比（AR（s-h））进行调节，从而导致可调的静态和动态润湿性。通过增加AR（s-h），（i）静态润湿性能，其特征在于使液滴能够降落在表面上的最小水滴体积，可以从1 μL调整到9 μL;（ii）滑动角可以灵活调整，范围从>90°（iii）液滴回弹行为可以从部分回弹调节到三重回弹。此外，本文还利用Cassie-Baxter模型和滑动角模型对接触角和滑动角进行了预测，为设计光滑-粘性超疏水表面提供了理论模型。飞秒激光微加工所获得的可调粘性超疏水表面可用于微流体系统中调节液滴的流动性。
In this paper, we present a new approach to the tunable adhesive superhydrophobic surfaces consisting of periodic hydrophobic patterns and superhydrophobic structures by femtosecond (fs) laser irradiation on silicon. The surfaces are composed of periodic hydrophobic patterns (triangle, circle, and rhombus) and superhydrophobic structures (dual-scale spikes induced by a fs laser). Our results reveal that the adhesive forces of as-prepared surfaces can be tuned by varying the area ratio (AR(s-h)) of superhydrophobic domain to hydrophobic domain, thus resulting in tunable static and dynamic wettabilities. By increasing AR(s-h), (i) the static wetting property, which is characterized by the minimum water droplet volume that enables a droplet to land on the surface, can be tailored from 1 μL to 9 μL; (ii) the sliding angle can be flexibly adjusted, ranging from >90° (a droplet cannot slide off when the sample is positioned upside down) to 5°; and (iii) the droplet rebound behaviors can be modulated from partial rebound to triple rebound. In addition, the Cassie-Baxter model and the sliding angle model are used to speculate the contact angles and sliding angles to provide potentially theoretical models to design slippery-to-sticky superhydrophobic surfaces. The tunable adhesive superhydrophobic surfaces achieved by fs laser microfabrication may be potentially used in microfluidic systems to modulate the mobility of liquid droplets.