自然界中許多動植物都具有超疏水的特性，其中蓮花葉面具有接觸角150∘、滑動角5∘的超疏水特性，且表面具防水、自潔以及可使液體在介面上滑動的能力，可應用於玻璃清潔、太陽能電池、交通工具以及家用衛浴等。近年對於基礎應用的研究十分廣泛。
基於仿生概念設計的凸柱狀微結構，因結構強度低易受到外力影響喪失疏水性以及自潔性，且製作成本較高、難以大量複製，因此在應用上受到較大的侷限。
本研究旨在設計創新微米級結構，相對於蓮花葉面以及一般較為常見的柱狀微結構，提出一種與此相反的半封閉性微結構，封閉處可將空氣困住，使之產生空氣彈簧的效果，超疏水性機制亦包含回復力與基材彈性。此半封閉性微結構之水滴接觸角可達168∘，滑動角約5∘，水滴撞擊微結構後可由表面反彈。
實驗主要探討微結構的接觸角，並以動態效應分析水滴撞擊不同微結構的反彈行為。除此之外也對實用性進行討論，實驗並分析此微結構對太陽能板發電效率的影響。

In nature, many of animals or plants have the feature of super-hydrophobicity. For example, leaves of lotus have the feature with 150° of contact angle and 5° of sliding angle, and the surface of leaves have the abilities of waterproofing, self-cleaning and making fluid sliding on the interface. This feature can be applied on glasses cleaning, solar cells, vehicles and sanitary equipment. The research of applications of this feature has been widely concerned in recent years.
Pillar structures, based on the concept of bionic, will lose the features of hydrophobicity and self-cleaning due to decreasing strength of structure caused by external force. Furthermore, the cost is expensive and also difficult to produce by a great amount. Therefore, the applications have numerous limitations.

The purpose of this research is to design an innovative micro-structure in micro level. Comparing to surface of lotus leaves and common pillar structures, this research proposed an opposite semi-mural micro-structure, where mural part can trap air in order to produce the effect of air spring. The mechanisms of super-hydrophobicity include the restoring force and the elastic deformation of the structure. This semi-mural micro-structure can reach 168° of contact angle and sliding angle about 5°. A water drop will rebound from the surface after impacting micro-structure.
This research mainly discussed about contact angle of micro-structure by experiments, and analyzed the behavior of water drop after impacting different micro-structure by dynamic effect. In addition, this research also discussed about practicability, and analyzed the effects of this micro-structure on efficiency of solar cells.

[1] A.B.D. Cassie and Baxter S., Wettability of Porous Surfaces. Trans. Faraday Soc. 40, 546-551 (1944)
[2] A. Marmur, Wetting on Hydrophobic Rough Surfaces: To Be Heterogeneous or Not To Be ?, Langmuir vol. 19, no. 20, pp. 8343–8348, (2003)
[3] Abraham Marmur, The Lotus Effect: Superhydrophobicity and Metastability, Langmuir vol. 20, 3517-3519(2004)
[4] B. Bhushan and Y. C. Jung, Wetting study of patterned surfaces for superhydrophobicity, Ultramicroscopy, Vol. 107, no. 10-11, pp.1033-1041,(2007).
[5] B. Bhushan, Y. C. Jung, and K. Koch, Micro-, Nano- and Hierarchical Structures for Superhydrophobicity, Self-Cleaning and Low Adhesion, Phil. Trans. R. Soc. 367(1894),1631-1672 (2009)
[6] B. Bhushan, and Y. C. Jung, and K. Koch, Self-Cleaning efficiency of artificial superhydrophobic surfaces. Langmuir. 25(5), 3240–3248.(2009)
[7] C. G. Furmidge, Studies at phase interfaces: Sliding of liquid drops on solid surfaces and a theory for spray retention, Journal of Colloid Science. 17(4), 309 (1962)
[8] C. Neinhuis and W. Barthlott, Characterization and Distribution of Water-repellent, Self-cleaning Plant Surfaces, Annals of Botany. 79, 667-677 (1997)
[9] D. Richard and D. Quéré, Bouncing water drops, Europhys. Lett. vol. 50, pp. 769, (2000).
[10] D. Richard, C. Clanet and D. Quéré, Contact time of a bouncing drop, Nature. 417, 811 (2002).
[11] D. Quéré, Non-sticking drops, INSTITUTE OF PHYSICS PUBLISHING. 68, 2495–2532 (2005).
[12] D. Bartolo, C. Josserand and D. Bonn, Retraction dynamics of aqueous drops upon impact on non-wetting surfaces, J. Fluid Mech., 545, 329-338 (2005).
[13] D. Quéré, Bouncing transitions on microtextured materials, Europhys. Lett. 74, 306 (2006).
[14] Daoai Wang, Xiaolong Wang, Xinjie Liu, and Feng Zhou, Engineering a Titanium Surface with Controllable Oleophobicity and Switchable Oil Adhesion, J. Phys. Chem. C 2010, 114, 9938–9944(2010)
[15] G. McHale, N. J. Shirtcliffe, and M. I. Newton, Contact-Angle Hysteresis on Super-Hydrophobic Surfaces, Langmuir, 20, 10146-10149(2004)
[16] H. Gao, X. Wang, H. Yao, S. Gorb and E. Arzt, Mechanics of hierarchical adhesion structures of geckos, Mechanics of Materials. 37, 275–285 (2005).
[17] Hua Zhou , Hongxia Wang , Haitao Niu , Adrian Gestos , Xungai Wang , and Tong Lin, Fluoroalkyl Silane Modifi ed Silicone Rubber/Nanoparticle Composite: A Super Durable, Robust Superhydrophobic Fabric Coating, Adv. Mater., 24, 2409–2412,( 2012)
[18] J. Bico, C. Marzolin and D. Quéré, Pearl drops. Europhys. Lett., 47(2),220–226(1999)
[19] J. Bico, U. Thiele and D. Quéré, Wetting of textured surfaces. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 206(9), 41–46 (2002).
[20] J. P. Rothstein, Slip on Superhydrophoboic Surface. Annual Review of Fluid Mechanics. 42, 89–109 (2010).
[21] Jia Zhu, Ching-Mei Hsu, Zongfu Yu, Shanhui Fan, and Yi Cui., Nanodome Solar Cells with Efficient Light Management and Self-Cleaning, Nano Lett., 10, 1979–1984(2010)
[22] Jiale Yong, Feng Chen, Qing Yang, Dongshi Zhang, Hao Bian, Guangqing Du, Jinhai Si, Xiangwei Meng, and Xun Hou, Controllable Adhesive Superhydrophobic Surfaces Based on PDMS Microwell Arrays, Langmuir 29, 3274−3279(2012)
[23] K. Koch, B. Bhushan, and W. Barthlott, Multifunctional Surface Structures of Plants: An Inspiration for Biomimetics, Progress in Materials Science. 54, 137-178 (2009).
[24] Lichao Gao and Thomas J. McCarthy, The “Lotus Effect” Explained: Two Reasons Why Two Length Scales of Topography Are Important, Langmuir, 22, 2966-2967(2006)
[25] Liangliang Cao, Andrew K. Jones, Vinod K. Sikka, Jianzhong Wu and Di Gao, Anti-Icing Superhydrophobic Coatings, Langmuir. 25(21), 12444-12448 (2009).
[26] Lidiya Mishchenko, Benjamin Hatton, Vaibhav Bahadur, J. Ashley Taylor, Tom Krupenkin,§andJoanna Aizenberg, Design of Ice-free Nanostructured Surfaces Based on Repulsion of Impacting Water droplets, ASC NANO, Vol 4, No. 12, (2010)
[27] Longquan Chen, Zhiyong Xiaob, Philip C.H. Chanc, Yi-Kuen Leea, Zhigang Li, A comparative study of droplet impact dynamics on a dual-scaled superhydrophobic surface and lotus leaf, Applied Surface Science 257 , 8857– 8863(2011)
[28] M. Pasandideh-Fard, Y. M. Qiao, S. Chandra, and J. Mostaghimi, Capillary effects during droplet impact on a solid surface, Phys. Fluids. 5, 650-659 (1996).
[29] M. Miwa, Akira Nakajima, Akira Fujishima, Kazuhito Hashimoto, and Toshiya Watanabe, Effects of the Surface Roughness on Sliding Angles of Water Droplets on Superhydrophobic Surfaces, Langmuir, vol. 16, no. 13, pp. 5754–5760, (2000).
[30] Morteza Mohammadia, Sara Moghtadernejadb, Percival J. Grahamc and Ali Dolatabadi, Dynamic Impact behavior of water droplet on a superhydrophobic surface in the presence of stagnation flow, Applied Mechanics and Materials Vol. 232 (2012) pp 267-272(2012)
[31] Peichun Tsai, Sergio Pacheco, Christophe Pirat, Leon Lefferts, and Detlef Lohse, Drop impact upon micro- and nanostructured superhydrophobic surfaces, Langmuir, 25 (20), pp 12293–12298(2009)
[32] Q. S. Zheng, Y. Yu, and Z. H. Zhao, Effects of Hydraulic Pressure on the Stability and Transition of Wetting Modes of Superhydrophobic Surfaces, Langmuir, vol. 21, no. 26, pp. 12207–12212,(2005).
[33] R. N. Wenzel, Resistance of solid surface to wetting by water. Ind. Eng.Chem. 28, 988 (1936).
[34] Rioboo R., Marengo M. and Tropea C., Time evolution of liquid drop impact onto solid, dry surfaces, Experiments in Fluids. 33, 112-124 (2002)
[35] R. Aikifa, S. Yang, W. Xianfeng, R. Tao, D. Bin, Y. Jianyong, and S. A. Salem, Novel fluorinated polybenzoxazine–silica films: chemical synthesis and superhydrophobicity, RSC Advances. 2,12804-12811 (2012).
[36] Š. Šikalo, M. Marengo, C. Tropea and E.N. Ganić, Analysis of impact of droplets on horizontal surface, Experimental Thermal and Fluid Science. 25, 503-510 (2002).
[37] Šikalo Š., Tropea C. and Ganić E.N. Dynamic wetting angle of a spreading droplet, Experimental Thermal and Fluid Science. 29(7), 795-802 (2005)
[38] Sang Eon Lee, Dongjin Lee, Phillip Lee, Seung Hwan Ko, Seung S. Lee, Seong Uk Hong, Flexible Superhydrophobic Polymeric Surfaces with Micro-/Nanohybrid Structures Using Black Silicon, Macromol. Mater. Eng., 298, 311–317,(2013)
[39] Thomas Young, An Essay on the Cohesion of Fluids. Phil. Trans. R. Soc. Lond. 95, 65–87 (1805).
[40] T. Mao, D.C.S. Kuhn and H. Tran, Spread and Rebound of Liquid Droplets upon Impact on Flat Surfaces, AIChE J. 43(9), 2169-2179 (1997).
[41] W. E., Squamation and ecology of sharks, Courier Forschungsinstitut Senckenberg. 78, 1–255 (1985).
[42] X. F. Gao and L. Jiang, Biophysics: Water-repellent Legs of Water Striders, Nature. 432, 36 (2004).
[43] Xiying Li, Liqun Mao, and Xuehu Ma, Dynamic Behavior of Water Droplet Impact on Microtextured Surfaces: The Effect of Geometrical Parameters on Anisotropic Wetting and the Maximum Spreading Diameter, Langmuir 29, 1129−1138(2012)
[44] Y. Bar-Cohen, Biomimetics: biologically inspired technologies, Boca Raton, Taylor and Francis. ,(2006).
[45] Y. C. Jung and B. Bhushan, Contact angle, adhesion and friction properties of micro- and nanopatterned polymers for superhydrophobicity, Nanotechnology, vol. 17, pp. 4970, (2006).
[46] Y. C. Jung and B. Bhushan, Dynamic Effects of Bouncing Water Droplets on Superhydrophobic Surfaces, Nanotechnology. 17, 4970–4980 (2006).
[47] Yong Chae Jung and Bharat Bhushan, Dynamic Effects of Bouncing Water Droplets on Superhydrophobic Surfaces, Langmuir, 24, 6262-6269.(2008)
[48] Yong Chae Jung and Bharat Bhushan, Dynamic Effects Induced Transition of Droplets on Biomimetic Superhydrophobic Surfaces, Langmuir, 25(16), 9208–9218(2009)
[49] Yong-Bum Park, Hwon Im, Maesoon Im‡ and Yang-Kyu Choi, Self-cleaning effect of highly water-repellent microshell structures for solar cell applications, J. Mater. Chem., 21, 633–636(2011)
[50] Z. Yoshimitsu, A. Nakajima, T. Watanabe, and K. Hashimoto, Effects of Surface Structure on the Hydrophobicity and Sliding Behavior of Water Droplets, Langmuir, 18, 5815-5822(2002).
[51] 張維仁，影響灰塵汙染建築物外壁材料諸因子之研究，國立中央大學碩士論文(1993)。
[52] 廖士貴, 國立成功大學機械工程學系碩士論文 (2010)
[53] 陳彥君, 國立成功大學機械工程學系碩士論文 (2011)
[54] 石嘉嘉, 國立成功大學機械工程學系碩士論文 (2012).
[55] 蕭舜心, 國立成功大學機械工程學系碩士論文 (2013)
[56] 楊家明, 國立成功大學機械工程學系碩士論文 (2014)