Hsiao Min, Chen Kai-Yu, Chen Chia-Yun
Department of Materials Science and Engineering, National Cheng Kung University, Tainan, 70101, Taiwan.
Hierarchical Green-Energy Materials (Hi-GEM) Research Center, National Cheng Kung University, Tainan, 70101, Taiwan.
Sci Rep. 2019 Feb 7;9(1):1579. doi: 10.1038/s41598-018-37853-4.
Surface hydrophobicity of silicon with sound durability under mechanical abrasion is highly desirable for practical needs. However, the reported micro-pyramid/nanowires structures suffer from the saturation characteristics of contact angle at around 132 degree, which impede the promotions toward reaching the state of superhydrophobicity. The present study focuses on the realization of two-scale silicon hierarchical structures prepared with the facile, rapid and large-area capable chemical etching methods without the need of lithographic patterning. The designed structures, with the well combination of microscale inverted pyramids and nanowire arrays, dramatically lead to the increased wetting angle of 157.2 degree and contact-angle hysteresis of 9.4 degree. In addition, the robustness test reveals that these hierarchical textures possess the narrow contact-angle change of 4 degree responding to the varied pH values, and maintain a narrow deviation of 2 degree in wetting angle after experiencing the abrasion test. Moreover, the highly stable photodetection characteristics of such two-scale structures were identified, showing the reliable photocurrents with less than 3% of deviation under wide range of environmental humidity. By adopting a simple chemical treatment, the wetting control is demonstrated for reliable transition of superhydrophobicity and superhydrophilicity.
具有良好机械耐磨性的硅表面疏水性对于实际应用需求而言是非常理想的。然而，已报道的微金字塔/纳米线结构存在接触角在132度左右的饱和特性，这阻碍了向超疏水状态的推进。本研究聚焦于通过无需光刻图案化的简便、快速且可大面积制备的化学蚀刻方法来实现两尺度硅分级结构。所设计的结构，将微尺度倒金字塔和纳米线阵列良好结合，显著使润湿角增加到157.2度，接触角滞后为9.4度。此外，稳健性测试表明，这些分级纹理在不同pH值下接触角变化仅为4度，并且在经受磨损测试后润湿角偏差保持在2度以内。而且，已确定这种两尺度结构具有高度稳定的光电探测特性，在宽范围环境湿度下显示出偏差小于3%的可靠光电流。通过采用简单的化学处理，展示了超疏水和超亲水之间可靠转变的润湿控制。
