A Sequential Process for Manufacturing Nature-Inspired Anisotropic Superhydrophobic Structures on AISI 316L Stainless Steel
A Sequential Process for Manufacturing Nature-Inspired Anisotropic Superhydrophobic Structures on AISI 316L Stainless Steel
复制标题
DOI：
10.1007/s41871-019-00046-2
复制
发表时间：
2019-08
影响因子：
--
通讯作者：
Yukui Cai;Zongwei Xu;Hong Wang;K. H. Lau;Fei Ding;Jining Sun;Y. Qin;Xichun Luo
中科院分区：
文献类型：
--
作者：
Yukui Cai;Zongwei Xu;Hong Wang;K. H. Lau;Fei Ding;Jining Sun;Y. Qin;Xichun Luo
具有各向异性超疏水性的表面由于其独特的减阻和单向流体传输特性，在药物输送和微流控器件中具有巨大的应用潜力。对自然生物表面的观察已经证明，定向微结构对于实现各向异性超疏水性是必不可少的。然而，目前基于光刻的制造方法对于现实世界的工业应用而言具有有限的放大能力。本文提出了一种激光烧蚀和化学蚀刻的顺序工艺，首次在AISI 316L不锈钢上制造棘轮状微结构，通过收集两种方法的优点。激光烧蚀会在试样表面形成特定的重铸层，重铸层上覆盖有氧化层，而这两层在化学腐蚀过程中可以很容易地去除，从而获得周期性的棘轮状微结构。根据实验结果，微结构的方向由激光束的进给方向决定。随着激光功率的增加，微结构的宽度和深度都增加，导致微结构中的脊消失。然而，增加的间距将导致脊再次出现。在20 W激光功率下加工的间距为25 μm的试样的最大接触角为158.2°。此外，当倾角为7°时，该样品显示出较强的各向异性超疏水性，液滴容易在激光束进给方向上滚离表面;然而，它在相反方向上被紧紧地钉扎。
Surfaces with anisotropic superhydrophobicity have great potential applications in drug delivery and microfluidic devices due to their unique properties of drag reduction and unidirectional fluid transportation. Observations of natural biological surfaces have proven that directional microstructures are indispensable for realizing anisotropic superhydrophobicity. However, current lithography-based manufacturing approaches have limited capabilities to scale-up for real-world industrial applications. This paper proposes a sequential process of laser ablation and chemical etching, for the first time, to manufacture ratchet-like microstructures on AISI 316L stainless steel by harvesting the advantages of both methods. The laser ablation will form a specified recast layer that will be covered by an oxide layer on the specimen, and these two layers can be easily removed in the chemical etching process to obtain the periodic ratchet-like microstructures. According to the experimental results, the direction of the microstructures is determined by the laser beam feed direction. Both the width and depth of microstructures increase with increasing laser power, which results in the disappearance of ridges. However, the increasing pitch will lead to the ridges appearing again. The specimen with a pitch of 25 μm machined at a laser power of 20 W has a maximum contact angle of 158.2°. Moreover, with a dip angle of 7°, this specimen shows a strong anisotropic superhydrophobicity, the droplet easily rolls off the surface in the laser beam feed direction; however, it is pinned tightly in the opposite direction.