摘要Manipulating the directional movement of liquid droplets is of significance for design and fabrication of some microfluidic devices. An energy-based method is adopted to analyse the directional movement of a droplet deposited in a conical tube or on a conical fibre. We perform an experiment to investigate the directional motion of a droplet in an open conical tube. Our theoretical analysis and experimental observations both demonstrate that surface tension can drive the droplet to move in the conical tube. The critical condition of the liquid moving in the conical tube is presented. We also analyse a droplet on a conical hydrophilic fibre, which can move from the thinner to the thicker end.
Abstract：Manipulating the directional movement of liquid droplets is of significance for design and fabrication of some microfluidic devices. An energy-based method is adopted to analyse the directional movement of a droplet deposited in a conical tube or on a conical fibre. We perform an experiment to investigate the directional motion of a droplet in an open conical tube. Our theoretical analysis and experimental observations both demonstrate that surface tension can drive the droplet to move in the conical tube. The critical condition of the liquid moving in the conical tube is presented. We also analyse a droplet on a conical hydrophilic fibre, which can move from the thinner to the thicker end.
LIU Jian-Lin;XIA Re;LI Bing-Wei;FENG Xi-Qiao. Directional Motion of Droplets in a Conical Tube or on a Conical Fibre[J]. 中国物理快报, 2007, 24(11): 3210-3213.
LIU Jian-Lin, XIA Re, LI Bing-Wei, FENG Xi-Qiao. Directional Motion of Droplets in a Conical Tube or on a Conical Fibre. Chin. Phys. Lett., 2007, 24(11): 3210-3213.
[1]Zhao B, Moore L S, and Beebe D L 2001 Science 291 1023 [2] Yue R F, Wu J G, Zeng X F, Kang M and Liu L T 2006 Chin.Phys. Lett. 23 2303 [3] Stewart D 2004 Nat. Wildlife 42 52 [4] Whitesides G M and Grzybowski B 2002 Science 295 2418 [5] Su M 2007 Appl. Phys. Lett. 90 144102 [6] Brochard F 1989 Langmuir 5 432 [7] Marangoni C 1871 Ann. Phys. Chem. 143 337 [8] Bico J and Quere D 2000 Europhys. Lett. 51 546 [9] Bico J and Quere D 2002 J. Fluid Mech. 467 101 [10] Weislogel M M 1997 AICHE J. 43 645 [11] Chaudhury M M and Whitesides G M 1992 Science 2561539 [12] Daniel S, Chaudhury M K and Chen J C 2001 Science 291633 [13] Lorenceau E and Quere D 2004 J. Fluid Mech. 510 29 [14] Hauksbee T 1712 Philosoph Transact. 27 395 [15] Bouasse H 1924 Capillarite, Phenomenes Superficiels (Paris:Delagrave) [16] Darhuber A A and Troian S M 2005 Annu. Rev. Fluid Mech. 37 425 [17] Young T 1805 Phil. T. Roy. Soc. London 95 65 [18] Adamson A W 1990 Physical Chemistry of Surfaces (New York:Wiley) [19] Feng X Q, Gao X F, Wu Z N, Jiang L and Zheng Q S 2007 Langmuir 23 4892
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