自然界中的蓮花葉面具有超疏水之特性，其接觸角約150°、滑動角約5°。其表面具能防水、自潔和流體滑動於界面之能力，可應用於玻璃清潔、太陽能電池、古蹟之保存、高樓、浴室及交通工具之清潔，而其滑動之邊界效應具應用於生物醫學方面之潛能。基於仿生學建立超疏水表面之結構，在近幾年引發極廣泛的基礎應用研究。然而該結構之結構強度低、大量複製困難，並易受外力受損失去自潔性的缺點。
本研究在於設計與分析一不具奈米纖維之創新微結構，其與自然者大不相同。相對於凸柱狀之蓮花結構，提出一種多層次之凹洞狀微結構，而凹洞內可困住空氣。造成其超疏水性之機制包括表面張力之回復力、基底材料之彈性、結構下層封閉性之空氣彈簧效應，結構上層減少液/固接觸面積以及所使用之疏水材料。實驗所用之微結構材料為聚二甲基矽氧烷(polydimethylsiloxane, PDMS)。理論與實驗上證實本半封閉性之反蓮花結構，其接觸角可達168°、滑動角約於5°，水滴可於微結構表面反彈，具有超疏水之性質。此超疏水表面不但有可大量生產之可行性，且具有較佳的結構強度，此研究設計結果於各領域皆具應用之潛能。

In nature, Leaves of Lotus are superhydrophobic surfaces. The contact angle is about 150° and slilding angle is below 5°. The surfaces have the abilities of water proofing, self-cleaning and slipping at the fluid-surface interface. Dominant applications can be found in the self-cleaning of glasses (window panes and windshields) and surfaces of solar cell, the protection of ancient remains, tall buildings, cars, bathrooms and structures in mountains. In addition, its slip boundary condition effect can potentially be applied in biomedicine. Based on the biomimicry, the study on creating super hydrophobic structures has triggered intense basic and applied research over the past several years. However, this kind of structures have some disadvantages, such as low structure strength and hard to replicate. It is easy to loss the ability of self-cleaning by the damage result from the external force.
In this study, we show that it is not correct and suitable to study the problem in the way of biomimicry. Here we propose an innovative novel super hydrophobic micro-structure without nano-fibers. Opposite to the pillar lotus structure, the proposed one is a multi-leveled concaved structure with trapped air. The mechanisms for repelling water include the restoring force due to surface tension, the elastic deformation of the structure, the air spring force resulting from the concaved structure with trapped air, low contact area and the used of hydrophobic material. The material of micro-structures is PDMS (polydimethylsiloxane). This study theoretically and experimentally demonstrates that multi-leveled and semi-mural micro-structure of negative lotus struture has the following charateristcsc which the contact angle is 168°, sliding angle is about 5°. Droplets will rebound on the micro-structure of the surface. Such superhydrophobic suface has the possibility of mass-fabricating and greater structural strength. The result of this research will have great potential of application in all kinds of field.

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