調控固體表面濕潤性程度，為防水、防汙及微流體等應用上的關鍵要素。藉由化學或物理的手段來達到改變表面濕潤性，然而，化學方式只具有短暫的效用，因此，透過表面粗糙化的物理方式則成為主流，引起許多研究者開始著手製作多種表面微結構以修飾疏水材料表面。
聚二甲基矽氧烷(Polydimethylsiloxane, PDMS)為一種有機高分子聚合物，展現高透光、可塑性及撓曲性，且具有低表面能的性質，為一款疏水性材料。因此，利用聚二甲基矽氧烷之良好的可加工性質，使用軟微影技術可將微結構圖案轉印至其表面上，且製備工作程序簡單且快速。
於本研究中，我們利用二次翻模轉印法將各向異性及各向同性微結構的疏水性葉面複印於聚二甲基矽氧烷表面，製作出具有微結構的疏水性表面。透過光學顯微鏡的觀察及接觸角與表面能的量測，探討樣品表面微結構排列分佈與其表面濕潤性之相關性。
研究發現樣品表面微結構的異向性排列引致表面能量異向性分佈，使液滴於平行葉脈方向受毛細作用力向前延展；而垂直葉脈方向則因微結構無序排列，致使液滴沿此方向延滯情形明顯，形成各向異性濕潤現象。其中具大黍微結構之聚二甲基矽氧烷樣品表面所呈現濕潤異向性及疏水特性最為顯著，可作為方向性自潔之應用。

Controlling wettability of solid surface plays an important role for applications in water-repellent, anti-fouling, microfluidics, and so on. Modification of surface wettability is achieved through either chemical or physical means; however, chemical means suffer the drawback of a short-lived effect. Therefore, physical means of modifying surface wettability are typically achieved through surface roughening, which caused many researchers began to fabricate a variety of surface microstructure to modification of hydrophobic material surface.
Polydimethylsiloxane, a silicon-based polymer, is a transparent, plastic and flexible material. Besides, the properties of low surface free energy makes it be hydrophobic. Accordingly, the use of PDMS with high plasticity to transfer the microstructure patterns to PDMS surfaces by soft lithography, and the production process is simple and efficient.
In this study, replica molding method is involved to produce the anisotropic and isotropic microstructures of hydrophobic leaves which are transferred to PDMS surfaces. After twice replica molding process, we duplicate the surface microtextures of the original leaves, enhancing the hydrophobicity of flat PDMS. Then we will observe surface morphology, contact angle and surface free energy to analyze microstructure distribution and surface wettability of PDMS samples. And we find that the anisotropic distribution of surface free energy will be caused by the anisotropic arrangement of PDMS surface microtextures. Accordingly, the length of the droplet is stretched since it is subjected to a capillary force parallel to the veins; however, due to the existence of the energy barrier in the direction perpendicular to the veins, the width of the droplet is shortened. The PDMS surface microstructures of Panicum maximum Jacq. with anisotropic wettability and hydrophobicity is the most significant among all leaves which can be applied to directional self-cleaning.

中文審定書........................................................................i
英文審定書.......................................................................ii
誌謝................................................................................iii
中文摘要..........................................................................iv
英文摘要...........................................................................v
第一章 緒論.....................................................................1
1-1 前言.....................................................................1
1-2 研究動機及研究內容...............................................3
第二章 研究理論介紹..........................................................4
2-1 表面張力................................................................4
2-2 靜態接觸角與表面濕潤性..........................................5
2-3 動態接觸角與接觸角延遲現象................................... 7
2-4 表面自由能及測定理論..............................................8
2-4-1 表面自由能...................................................... 8
2-4-2 表面自由能量測................................................ 9
2-5 表面濕潤模型理論....................................................11
2-5-1 Wenzel 模型....................................................11
2-5-2 Cassie-Baxter 模型..........................................12
2-5-3 Wenzel與Cassie-Baxter模型的接觸角遲滯現象...13
2-6 蓮葉效應(Lotus effect)..............................................15
第三章 實驗材料、樣品製備及儀器設備....................................17
3-1 聚二甲基矽氧烷........................................................17
3-2 樣品製備理論及流程.................................................19
3-2-1 翻模轉印法(Replica Molding Method, REM)........19
3-3 儀器設備介紹...........................................................21
3-3-1 正交偏光顯微鏡.................................................21
3-3-2 接觸角量測儀....................................................22
3-3-3 電漿清洗機........................................................23
第四章 疏水性植物葉面分析....................................................25
4-1 引言........................................................................25
4-2 植物葉面微結構觀察.................................................26
4-2-1 各向異性微結構................................................26
4-2-2 各向同性微結構................................................33
4-3 靜態接觸角量測........................................................36
4-3-1 各向異性微結構................................................36
4-3-2 各向同性微結構................................................38
第五章 具葉面微結構之聚二甲基矽氧烷表面特性分析................40
5-1 引言........................................................................40
5-2 聚二甲基矽氧烷樣品表面微結構觀察...........................41
5-2-1 各向異性微結構.................................................41
5-2-2 各向同性微結構.................................................46
5-3 靜態接觸角量測與液滴輪廓觀測..................................49
5-3-1 各向異性微結構.................................................49
5-3-2 各向同性微結構.................................................51
5-3-3 液滴靜態接觸角於微結構樣品表面分析與討論.......54
5-4 動態接觸角量測.........................................................56
5-4-1 各向異性微結構.................................................56
5-4-2 各向同性微結構.................................................58
5-5 表面能量測...............................................................61
5-5-1 各向異性微結構.................................................61
5-5-2 各向同性微結構.................................................64
第六章 總結與未來展望........................................................... 67
6-1 總結.........................................................................67
6-2 未來工作及展望.........................................................69
參考文獻................................................................................70

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