State Key Laboratory for Manufacturing System Engineering, School of Electronics and Information Engineering, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China.
ACS Appl Mater Interfaces. 2012 Sep 26;4(9):4905-12. doi: 10.1021/am3012388. Epub 2012 Aug 28.
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.
在本文中，我们提出了一种新的方法来制备可调谐粘性超疏水表面，该表面由周期性的疏水性图案和飞秒（fs）激光在硅上辐照产生的超疏水结构组成。这些表面由周期性的疏水性图案（三角形、圆形和菱形）和超疏水结构（由 fs 激光产生的双尺度刺）组成。我们的结果表明，通过改变超疏水域与疏水区域的面积比（AR(s-h)），可以调节制备表面的粘附力，从而实现对静态和动态润湿性的可调谐。通过增加 AR(s-h)：(i) 可以从 1 μL 到 9 μL 调节静态润湿性能，其特征是使液滴能够在表面上着陆的最小液滴体积；(ii) 滑动角可以灵活地调节，范围从>90°（当样品倒置时，液滴不会滑落）到 5°；以及 (iii) 液滴反弹行为可以从部分反弹到三重反弹进行调制。此外，使用 Cassie-Baxter 模型和滑动角模型来推测接触角和滑动角，为设计滑爽-粘性超疏水表面提供了潜在的理论模型。通过飞秒激光微加工实现的可调谐粘性超疏水表面可能在微流控系统中用于调节液滴的流动性。
