流體自我組裝為利用元件表面之親疏水性質差異進行組裝，本實驗即透過疏水材料PDMS於玻璃表面上進行改質，設計不同寬度之親水流道，以連續流體流經流道，藉由觀察流道流場分析親疏水界面對於水流動之影響。實驗結果顯示，(1)流體與親疏水邊界接觸時間之早晚會影響到流體整體流動之方向，以及單位時間內所流動之距離。(2)質量流率0.2g/min下，以Win=3mm、Wout=11mm之流道於相同時間上移動距離最遠；當質量流率為0.4g/min之後的流場行為約可縮短三分之一之流動時間；質量流率為1.0g/min時，則以Win=5mm、Wout=9mm流道移動距離為最遠，此參數條件為最佳流道設計型式。(3)就分段速率而言可分為三部分，分別為初始速率區、中間震盪區以及末端平緩流動區。(4)傾斜角度的增加能有效提升各流道之流動距離，但於Win=11mm、Wout=3mm之漸縮型流道，卻容易造成流體跨越親疏水邊界之臨界高度下降。(5)由無因次分析結果(We*/Fr*)可知，各參數下之流動情形可概分為兩大部分。

Fluidic Self-Assembly (FSA) is an assembly process which utilizes fluid to transport components and to assemble by hydrophobic interaction. This study explores the performance of continuous fluid flowing through the hydrophilic surface bound by hydrophobic and hydrophilic surface patterned by PDMS side by side. Key experimental results are as follows. First, the flowing directions and distances of fluid are affected by the contact timing with the hydrophobic interfaces. Second, the flow exhibits three regions of different velocities: the initial high velocity, the middle oscillatory velocity, and ending smooth velocity. Third, the increasing slope angles can increase the flowing distances. Finally, the dimensionless analysis shows two groups of flow situation.

[1] U. Srinivasan, D. Liepmann, and R. T. Howe, "Microstructure to substrate self-assembly using capillary forces," Journal of Microelectromechanical Systems, vol. 10, pp. 17-24, Mar 2001.

[2] B. Vogeli and H. von Kanel, "AFM-study of sticking effects for microparts handling," Wear, vol. 238, pp. 20-24, Mar 2000.

[3] R. Sharma, "Thermally controlled fluidic self-assembly," Langmuir, vol. 23, pp. 6843-6849, Jun 2007.

[4] G. M. Whitesides and B. Grzybowski, "Self-assembly at all scales," Science, vol. 295, pp. 2418-2421, Mar 2002.

[5] R. C. McPhedran, N. A. Nicorovici, D. R. McKenzie, L. C. Botten, A. R. Parker, and G. W. Rouse, "The sea mouse and the photonic crystal," Australian Journal of Chemistry, vol. 54, pp. 241-244, 2001.

[6] Y. S. Choi, J. Y. Lim, and K. S. Lee, "Development of a DNA chip microarray using hydrophobic interaction between template and particle by using the random fluidic self-assembly method," Current Applied Physics, vol. 7, Mar 2007.

[7] S. A. Stauth and B. A. Parviz, "Self-assembled single-crystal silicon circuits on plastic," Proceedings of the National Academy of Sciences of the United States of America, vol. 103, pp. 13922-13927, Sep 2006.

[8] U. Srinivasan, M. A. Helmbrecht, C. Rembe, R. S. Muller, and R. T. Howe, "Fluidic self-assembly of micromirrors onto microactuators using capillary forces," IEEE Journal of Selected Topics in Quantum Electronics, vol. 8, pp. 4-11, Jan-Feb 2002.

[9] H. J. J. Yeh and J. S. Smith, "Fluidic self-assembly for the integration of GaAs light-emitting diodes on Si substrates," IEEE Photonics Technology Letters, vol. 6, pp. 706-708, Jun 1994.

[10] http://www.alientechnology.com/

[11] H. Onoe, K. Matsumoto, and I. Shimoyama, "Three-dimensional micro-self-assembly using hydrophobic interaction controlled by self-assembled monolayers," Journal of Microelectromechanical Systems, vol. 13, pp. 603-611, Aug 2004.

[12] B. Zhao, J. S. Moore, and D. J. Beebe, "Surface-directed liquid flow inside microchannels," Science, vol. 291, pp. 1023-1026, Feb 2001.

[13] M. Rauscher and S. Dietrich, "Wetting phenomena in nanofluidics," Annual Review of Materials Research, vol. 38, pp. 143-172, 2008.

[14] M. Morita, T. Koga, H. Otsuka, and A. Takahara, "Macroscopic-wetting anisotropy on the line-patterned surface of fluoroalkylsilane monolayers," Langmuir, vol. 21, pp. 911-918, Feb 2005.

[15] A. K. Verma, M. A. Hadley, H.-J. J. Yeh, and J. S. Smith, "Fluidic self-assembly of silicon microstructures," in Proceedings. 45th Electronic Components and Technology Conference,, (Las Vegas, NV, USA), pp. 1263-1268, May 1995.

[16] J. J. Talghader, J. K. Tu, and J. S. Smith, "Integration of fluidically self-assembled optoelectronic devices using a silicon-based process," IEEE Photonics Technology Letters, vol. 7, pp. 1321-1323, 1995.

[17] D. H. Gracias, V. Kavthekar, J. C. Love, K. E. Paul, and G. M. Whitesides, "Fabrication of micrometer-scale, patterned polyhedra by self-assembly," Advanced Materials, vol. 14, pp. 235-+, Feb 2002.

[18] X. Xiong, K. Wang, and K. F. Bohringer, "From micro-patterns to nano-structures by controllable colloidal aggregation at air-water interface," in 17th IEEE International Conference on Micro Electro Mechanical Systems(MEMS’04), pp. 621-624, 2004.

[19] K. L. Scott, T. Hirano, H. Yang, R. T. Howe, and A. M. Niknejad, "High-performance inductors using capillary based fluidic self-assembly," Journal of Microelectromechanical Systems, vol. 13, pp. 300-309, Apr 2004.

[20] C. G. Tsai, C. M. Hsieh, and J. A. Yeh, "Self-alignment of microchips using surface tension and solid edge," Sensors and Actuators A: Physical, vol. 139, pp. 343-349, Sep. 2007.

[21] A. Terfort, N. Bowden, and G. M. Whitesides, "Three-dimensional self-assembly of millimetre-scale components," Nature, vol. 386, pp. 162-164, Mar 1997.

[22] A. Terfort and G. M. Whitesides, "Self-assembly of an operating electrical circuit based on shape complementarity and the hydrophobic effect," Advanced Materials, vol. 10, pp. 470-+, Apr 1998.

[23] J. W. Suk and J. H. Cho, "Capillary flow control using hydrophobic patterns," Journal of Micromechanics and Microengineering, vol. 17, pp. N11-N15, Apr 2007.

[24] U. Srinivasan, R. T. Howe, and D. Liepmann, " Fluidic microassembly using patterned self-assembled monolayers and shape matching," in Proc. 1999 Int. Conf. on Solid-State Sensors and Actuators, pp. 1170-1173, June 7-10 1999.

[25] X. Xiong, Y. Hanein, J. Fang, Y. Wang, W. Wang, D. T. Schwartz, and K. F. Bohringer, "Controlled multibatch self-assembly of microdevices," Journal of Microelectromechanical Systems, vol. 12, pp. 117-127, 2003.

[26] X. R. Xiong, Y. Hanein, J. D. Fang, Y. B. Wang, W. H. Wang, D. T. Schwartz, and K. F. Bohringer, "Controlled multibatch self-assembly of microdevices," Journal of Microelectromechanical Systems, vol. 12, pp. 117-127, Apr 2003.

[27] X. Yu, Z. Q. Wang, Y. G. Jiang, and X. Zhang, "Surface gradient material: From superhydrophobicity to superhydrophilicity," Langmuir, vol. 22, pp. 4483-4486, May 2006.

[28] M. Liu, W. M. Lau, and J. Yang, "On-demand multi-batch self-assembly of hybrid MEMS by patterning solders of different melting points," Journal of Micromechanics and Microengineering, vol. 17, pp. 2163-2168, Nov 2007.

[29] M. Sakai, J. H. Song, N. Yoshida, S. Suzuki, Y. Kameshima, and A. Nakajima, "Direct observation of internal fluidity in a water droplet during sliding on hydrophobic surfaces," Langmuir, vol. 22, pp. 4906-4909, May 2006.

[30] J. H. Song, M. Sakai, N. Yoshida, S. Suzuki, Y. Kameshima, and A. Nakajima, "Dynamic hydrophobicity of water droplets on the line-patterned hydrophobic surfaces," Surface Science, vol. 600, pp. 2711-2717, Jul 2006.

[31] S. Suzuki, A. Nakajima, K. Tanaka, M. Sakai, A. Hashimoto, N. Yoshida, Y. Kameshima, and K. Okada, "Sliding behavior of water droplets on line-patterned hydrophobic surfaces," Applied Surface Science, vol. 254, pp. 1797-1805, Jan 2008.

[32] H. Suda and S. Yamada, "Force measurements for the movement of a water drop on a surface with a surface tension gradient," Langmuir, vol. 19, pp. 529-531, Feb 2003.

[33] V. Jokinen and S. Franssila, "Capillarity in microfluidic channels with hydrophilic and hydrophobic walls," Microfluidics and Nanofluidics, vol. 5, pp. 443-448, Oct 2008.

[34] C. F. Kung, C. F. Chiu, C. F. Chen, C. C. Chang, and C. C. Chu, "Blood flow driven by surface tension in a microchannel," Microfluidics and Nanofluidics, vol. 6, pp. 693-697, May 2009.

[35] A. Mata, A. J. Fleischman, and S. Roy, "Characterization of polydimethylsiloxane (PDMS) properties for biomedical micro/nanosystems," Biomedical Microdevices, vol. 7, pp. 281-293, Dec 2005.