Microgravity Science and Technology

, Volume 30, Issue 4, pp 571–579 | Cite as

Droplet Movement on a Composite Wedge-Shaped Surface with Multi-Gradients and Different Gravitational Field by Molecular Dynamics

  • Bo Xu
  • Zhenqian ChenEmail author
Original Article


To find out the mechanism of droplet movement on the composite wedge-shaped surface with multi wettability gradients and simulated gravitational field in a micro view, the model of droplet movement was built and studied by molecular dynamics. It was found that the droplet would move faster and farther with greater vertex angle on hydrophobic surface than on hydrophilic surface until the whole droplet reached the strong wettability surface. Applied force was used to simulate gravitational field. An inflection point was appeared in the average velocity curve. The average velocity increased first and then decreased with greater applied force. The simulation results of relationship between average velocity and applied force corresponded well with nonlinear fitting curve, indicating the reasonable and reliable of simulation results. With the increase of applied force, the droplet became more flat. However, the effect of wettability gradient to shrink the spread area played a major role in the early to make the droplet narrower and then the combined effect of wettability gradient to enlarge the spread area and applied force had a major impact in the later to make the droplet spread more.


Droplet movement Composite wedge-shaped surface Multi wettability gradients Vertex angle Applied force Molecular dynamics 



This work was supported by the China’s Manned Space Program [grant number TZ-1] and Scientific Research Foundation of Graduate School of Southeast University [grant number YBJJ1602].


  1. Alexiadis, A., Kassinos, S.: Molecular simulation of water in carbon nanotubes. Chem. Rev. 108, 5014 (2008)CrossRefGoogle Scholar
  2. Bai, H., Tian, X.L., Zheng, Y.M., Ju, J., Zhao, Y., Jiang, L.: Direction controlled driving of tiny water drops on bioinspired artificial spider silks. Adv. Mater. 22, 5521–5525 (2010)CrossRefGoogle Scholar
  3. Cieplak, M., Koplik, J., Banavar, J.R.: Nanoscale fluid flows in the vicinity of patterned surfaces. Phys. Rev. Lett. 96, 114502 (2006)CrossRefGoogle Scholar
  4. Chaudhury, M.K., Whitesides, G.M.: How to make water run uphill. Science 256, 1539–1541 (1992)CrossRefGoogle Scholar
  5. Chen, Y., Wang, L., Xue, Y., Jiang, L., Zheng, Y.: Bioinspired tilt-angle fabricated structure gradient fibers: micro-drops fast transport in a long-distance. Sci. Rep., 3 (2013)Google Scholar
  6. Chen, X., Ding, Z.J., Liu, R.: Spreading of annular droplets on a horizontal fiber. Microgravity Sci. Technol. 30, 143–153 (2018)CrossRefGoogle Scholar
  7. Chou, I.H., Benford, M., Beier, H.T., Cote, G.L.: Nanofluidic biosensing for beta-amyloid detection using surface enhanced Raman spectroscopy. Nano Lett. 8, 1729–1735 (2008)CrossRefGoogle Scholar
  8. Daniel, S., Chaudhury, M.K., Chen, J.C.: Past drop movements resulting from the phase change on a gradient surface. Science 291, 633–636 (2001)CrossRefGoogle Scholar
  9. Daniel, S., Chaudhury, M.K., De Gennes, P.G.: Vibration-actuated drop motion on surfaces for batch microfluidic processes. Langmuir 21, 4240–4248 (2005)CrossRefGoogle Scholar
  10. De Coninck, J., Blake, T.D.: Wetting and molecular dynamics simulations of simple liquids. Annu. Rev. Mater. Res. 38, 1 (2008)CrossRefGoogle Scholar
  11. Deng, S., Shang, W., Feng, S., Zhu, S., Xing, Y., Li, D., Hou, Y., Zheng, Y.: Controlled droplet transport to target on a high adhesion surface with multi-gradients. Sci. Rep., 7 (2017a)Google Scholar
  12. Deng, S.Y., Shang, W.F., Feng, S.L., Zhu, S.P., Xing, Y., Li, D., Hou, Y.P., Zheng, Y.M.: Controlled droplet transport to target on a high adhesion surface with multi-gradients. Sci. Rep-UK, 45687 (2017b)Google Scholar
  13. Furuta, T., Sakai, M., Isobe, T., Matsushita, S., Nakajima, A.: Sliding of water droplets on hydrophobic surfaces with various hydrophilic region sizes. Langmuir 27, 7307–7313 (2011)CrossRefGoogle Scholar
  14. Greenspan, H.P.: Motion of a small viscous droplet that wets a surface. J. Fluid Mech. 84, 125–143 (1978)CrossRefzbMATHGoogle Scholar
  15. Guo, L., Tang, G.H.: Experimental study on directional motion of a single droplet on cactus spines. Int. J. Heat Mass Trans. 84, 198–202 (2015)CrossRefGoogle Scholar
  16. Ghosh, A., Ganguly, R., Schutzius, T.M., Megaridis, C.M.: Wettability patterning for high-rate, pumpless fluid transport on open, non-planar microfluidic platforms. Lab Chip 14, 1538–1550 (2014)CrossRefGoogle Scholar
  17. Grunze, M.: Surface science - driven liquids. Science 283, 41–42 (1999)CrossRefGoogle Scholar
  18. Halverson, J.D., Maldarelli, C., Couzis, A., Koplik, J.: A molecular dynamics study of the motion of a nanodroplet of pure liquid on a wetting gradient. J. Chem. Phys. 129, 164708 (2008)CrossRefGoogle Scholar
  19. Hoover, W.G.: Canonical dynamics: equilibrium phase-space distributions. Phys. Rev. A 31, 1695 (1985)CrossRefGoogle Scholar
  20. Ito, Y., Heydari, M., Hashimoto, A., Konno, T., Hirasawa, A., Hori, S., Kurita, K., Nakajima, A.: The movement of a water droplet on a gradient surface prepared by photodegradation. Langmuir 23, 1845–1850 (2007)CrossRefGoogle Scholar
  21. Ju, J., Bai, H., Zheng, Y., Zhao, T., Fang, R., Jiang, L.: A multi-structural and multi-functional integrated fog collection system in cactus. Nat. Commun. 3, 1247 (2012)CrossRefGoogle Scholar
  22. Ju, J., Xiao, K., Yao, X., Bai, H., Jiang, L.: Bioinspired conical copper wire with gradient wettability for continuous and efficient fog collection. Adv. Mater. 25, 5937–5942 (2013)CrossRefGoogle Scholar
  23. Koishi, T., Yasuoka, K., Fujikawa, S., Ebisuzaki, T., Zeng, X.C.: Coexistence and transition between Cassie and Wenzel state on pillared hydrophobic surface. PNAS 106, 8435–8440 (2009)CrossRefGoogle Scholar
  24. Koishi, T., Yasuoka, K., Fujikawa, S., Zeng, X.C.: Measurement of contact-angle hysteresis for droplets on nanopillared surface and in the Cassie and Wenzel states: a molecular dynamics simulation study. ACS Nano 5, 6834–6842 (2011)CrossRefGoogle Scholar
  25. Kostoglou, M., Karapantsios, T.D., Buffone, C., Glushchuk, A., Iorio, C.: A theoretical study of steady state and transient condensation on axisymmetric fins under combined capillary and gravitational forces. Microgravity Sci. Technol. 28, 559–567 (2016)CrossRefGoogle Scholar
  26. Kou, J.L., Mei, M.F., Lu, H.J., Wu, F.M., Fan, J.T.: Unidirectional motion of a water nanodroplet subjected to a surface energy gradient. Phys. Rev. E 85, 056301 (2012)CrossRefGoogle Scholar
  27. Lei, Y.C., Chen, Z.Q., Shi, J.: Analysis of condensation heat transfer performance in curved triangle microchannels based on the volume of fluid method. Microgravity Sci. Technol. 29, 433–443 (2017)CrossRefGoogle Scholar
  28. Li, P.P., Chen, Z.Q., Shi, J.: Numerical study on the effects of gravity and surface tension on condensation process in square minichannel. Microgravity Sci. Technol. 30, 19–24 (2018)CrossRefGoogle Scholar
  29. Li, K., Ju, J., Xue, Z., Ma, J., Feng, L., Gao, S., Jiang, L.: Structured cone arrays for continuous and effective collection of micron-sized oil droplets from water. Nat. Commun. 4, 2276 (2013)CrossRefGoogle Scholar
  30. Lundgren, M., Neil, L.A., Terence, C.: Modeling of wetting: a study of nanowetting at rough and heterogeneous surfaces. Langmuir 23, 1187–1194 (2007)CrossRefGoogle Scholar
  31. Lv, C.J., Chen, C., Chuang, Y.C., Tseng, F.G., Yin, Y.J., Grey, F., Zheng, Q.S.: Substrate curvature gradient drives rapid droplet motion. Phys. Rev. Lett. 113, 026101 (2014)CrossRefGoogle Scholar
  32. Martin, B., Hervé, C., Youen, V., Stéphane, D.: Electrically charged droplets in microgravity. Microgravity Sci. Technol. 29, 229–239 (2017)CrossRefGoogle Scholar
  33. Paradisanos, I., Fotakis, C., Anastasiadis, S.H., Stratakis, E.: Gradient induced liquid motion on laser structured black Si surfaces. Appl. Phys. Lett. 107, 111603 (2015)CrossRefGoogle Scholar
  34. Plimpton, S.: Fast parallel algorithms for short-range molecular dynamics. J. Comput. Phys. 117(1), 1–19 (1995)CrossRefzbMATHGoogle Scholar
  35. Price, S.L., Stone, A.J., Alderton, M.: Explicit formulae for the electrostatic energy, forces and torques between a pair of molecules of arbitrary symmetry. Mol. Phys. 52(7), 987–1001 (1984)CrossRefGoogle Scholar
  36. Tan, X., Zhu, Y., Shi, T., Tang, Z., Liao, G.: Patterned gradient surface for spontaneous droplet transportation and water collection: simulation and experiment. J. Micromech. Microeng. 26, 115009 (2016)CrossRefGoogle Scholar
  37. Tian, X., Chen, Y., Zheng, Y., Bai, H., Jiang, L.: Controlling water capture of bioinspired fibers with hump structures. Adv. Mater. 23, 5486–5491 (2011)CrossRefGoogle Scholar
  38. Wang, F.C., Yang, F., Zhao, Y.P.: Size effect on the coalescence-induced self-propelled droplet. Appl. Phys. Lett. 98, 053112 (2011)CrossRefGoogle Scholar
  39. Wang, T., Li, W., Liu, L., Chen, H.X., Wang, Y.F., Zhang, J., Yan, Y.G.: The mechanism for the motion of nanoscale water droplet induced by wetting gradient: a molecular dynamic study. Comput. Mater. Sci. 105, 39–46 (2015)CrossRefGoogle Scholar
  40. Xu, T., Lin, Y., Zhang, M., Shi, W., Zheng, Y.: High-efficiency fog collector: water unidirectional transport on heterogeneous rough conical wires. ACS Nano 10, 10681–10688 (2016)CrossRefGoogle Scholar
  41. Yen, T.H.: Wetting characteristics of nanoscale water droplet on silicon substrates with effects of surface morphology. Mol. Simulat. 37, 766–778 (2011)CrossRefGoogle Scholar
  42. Yong, X., Zhang, L.T.: Nanoscale wetting on groove-patterned surfaces. Langmuir 25, 5045–5053 (2009)CrossRefGoogle Scholar
  43. You, I., Lee, T.G., Nam, Y.S., Lee, H.: Fabrication of a micro-omnifluidic Device by omniphilic/omniphobic patterning on nanostructured surfaces. ACS Nano 8, 9016–9024 (2014)CrossRefGoogle Scholar
  44. Zhang, L.G., Shi, J., Xu, B., Chen, Z.Q.: Experimental study on distribution characteristics of condensate droplets under ultrasonic vibration. Microgravity Sci. Technol., 1–10 (2018)Google Scholar
  45. Zhang, J., Han, Y.: Shape-gradient composite surfaces: water droplets move uphill. Langmuir 23, 6136–6141 (2007a)Google Scholar
  46. Zhang, J.L., Han, Y.C.: Shape-gradient composite surfaces: water droplets move uphill. Langmuir 23, 6136–3414 (2007b)Google Scholar
  47. Zhang, K., Wang, F.H., Zhao, X.: The self-propelled movement of the water nanodroplet in different surface wettability gradients: a contact angle view. Comput. Mater. Sci. 124, 190–194 (2016)CrossRefGoogle Scholar
  48. Zheng, Y., Bai, H., Huang, Z., Tian, X., Nie, F.Q., Zhao, Y., Jiang, L.: Directional water collection on wetted spider silk. Nature 463, 640 (2010)CrossRefGoogle Scholar
  49. Zou, Z.Z., Luo, X.H., Yu, Q.: Droplet image super resolution based on sparse representation and kernel regression. Microgravity Sci. Technol. 30, 321–329 (2018)CrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2018

Authors and Affiliations

  1. 1.School of Energy and EnvironmentSoutheast UniversityNanjingPeople’s Republic of China
  2. 2.Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology, School of Energy and EnvironmentSoutheast UniversityNanjingPeople’s Republic of China

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