Ding Yong, Xu Sheng, Zhang Yue, Wang Aurelia C, Wang Melissa H, Xiu Yonghao, Wong Ching Ping, Wang Zhong Lin
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245, USA.
Nanotechnology. 2008 Sep 3;19(35):355708. doi: 10.1088/0957-4484/19/35/355708. Epub 2008 Jul 18.
Although butterfly wings and water strider legs have an anti-wetting property, their working conditions are quite different. Water striders, for example, live in a wet environment and their legs need to support their weight and bear the high pressure during motion. In this work, we have focused on the importance of the surface geometrical structures in determining their performance. We have applied an atomic layer deposition technique to coat the surfaces of both butterfly wings and water strider legs with a uniform 30 nm thick hydrophilic Al(2)O(3) film. By keeping the surface material the same, we have studied the effect of different surface roughness/structure on their hydrophobic property. After the surface coating, the butterfly wings changed to become hydrophilic, while the water strider legs still remained super-hydrophobic. We suggest that the super-hydrophobic property of the water strider is due to the special shape of the long inclining spindly cone-shaped setae at the surface. The roughness in the surface can enhance the natural tendency to be hydrophobic or hydrophilic, while the roughness in the normal direction of the surface is favorable for forming a composite interface.
虽然蝴蝶翅膀和水黾腿具有抗湿特性，但它们的工作条件却大不相同。例如，水黾生活在潮湿环境中，其腿部需要支撑自身重量并在运动时承受高压。在这项工作中，我们着重研究了表面几何结构在决定其性能方面的重要性。我们应用原子层沉积技术，在蝴蝶翅膀和水黾腿的表面均涂上一层均匀的30纳米厚的亲水性Al₂O₃薄膜。通过保持表面材料相同，我们研究了不同表面粗糙度/结构对其疏水性能的影响。表面涂层后，蝴蝶翅膀变为亲水性，而水黾腿仍保持超疏水性。我们认为水黾的超疏水性是由于其表面长而倾斜的细长锥形刚毛的特殊形状所致。表面粗糙度可增强其疏水或亲水的自然倾向，而表面法线方向的粗糙度有利于形成复合界面。
