Skip to main content Accessibility help
×
Home

Liquid spreading on superhydrophilic micropillar arrays

  • SEONG JIN KIM (a1), MYOUNG-WOON MOON (a2), KWANG-RYEOL LEE (a2), DAE-YOUNG LEE (a2), YOUNG SOO CHANG (a3) and HO-YOUNG KIM (a1)...

Abstract

When a drop is deposited on a superhydrophilic micropillar array, the upper part of the drop (referred to as the bulk) collapses while the bottom part penetrates into the gaps of the array, forming a fringe film. Here we quantify the early stage dynamics of this process using a combination of experiment and theory. We show that the circular front of the fringe film spreads like t1/2, t being time, when coupled to the bulk flow. However, the film is found to advance like t1/3 through faceted zippering in the absence of the bulk. We then show that the spreading of the bulk and the entire drop footprint follows a power law (t1/4) that is different from Washburn's law. This work can be a starting point to completely understand the spreading of liquids on superhydrophilic surfaces and opens questions specific to superwetting behaviour including the criteria to determine whether the fringe film will expand through lateral zipping or advance radially outwards.

Copyright

Corresponding author

Email address for correspondence: hyk@snu.ac.kr

References

Hide All
Biance, A.-L., Clanet, C. & Quéré, D. 2004 First steps in the spreading of a liquid droplet. Phys. Rev. E 69, 016301.
Brochard-Wyart, F., Debrégeas, G. & de Gennes, P. G. 1996 Spreading of viscous droplets on a non viscous liquid. Colloid Polym. Sci. 274, 7072.
Cassie, A. B. D. & Baxter, S. 1944 Wettability of porous surfaces. Trans. Faraday Soc. 40, 546551.
Courbin, L., Denieul, E., Dressaire, E., Roper, M., Ajdari, A. & Stone, H. A. 2007 Imbibition by polygonal spreading on microdecorated surfaces. Nature Mater. 6, 660664.
de Gennes, P. G. 1985 Wetting: statics and dynamics. Rev. Mod. Phys. 57, 827863.
Ehrhard, P. 1993 Experiments on isothermal and non-isothermal spreading. J. Fluid Mech. 257, 463483.
Huppert, H. E. 1982 The propagation of two-dimensional and axisymmetric viscous gravity currents over a rigid horizontal surface. J. Fluid Mech. 121, 4358.
Ishino, C., Reyssat, M., Reyssat, E., Okumura, K. & Quéré, D. 2007 Wicking within forests of micropillars. Europhys. Lett. 79, 56005.
Lopez, J. & Miller, C. A. 1976 Spreading kinetics of liquid drops on solids. J. Colloid Interface Sci. 56 (3), 460468.
Maclaine-cross, I. L. & Banks, P. J. 1981 A general theory of wet surface heat exchangers and its application to regenerative evaporative cooling. Trans. ASME J. Heat Transfer 103, 579585.
Martinez, A. W., Phillips, S. T. & Whitesides, G. M. 2008 Three-dimensional microfluidic devices fabricated in layered paper and tape. Proc. Natl Acad. Sci. USA 105, 1960619611.
McHale, G., Shirtcliffe, N. J., Aqil, S., Perry, C. C. & Newton, M. I. 2004 Topography driven spreading. Phys. Rev. Lett. 93, 036102.
Reyssat, M., Courbin, L., Reyssat, E. & Stone, H. A. 2008 Imbibition in geometries with axial variations. J. Fluid Mech. 615, 335344.
Sbragaglia, M., Peters, A. M., Pirat, C., Borkent, B. M., Lammertink, R. G. H., Wessling, M. & Lohse, D. 2007 Spontaneous breakdown of superhydrophobicity. Phys. Rev. Lett. 99, 156001.
Tanner, L. H. 1979 The spreading of silicone oil drops on horizontal surfaces. J. Phys. D: Appl. Phys. 12, 14731484.
Teng, Y., Wang, R. Z. & Wu, J. Y. 1997 Study of the fundamentals of adsorption systems. Appl. Therm. Engng 17, 327338.
Washburn, E. W. 1921 The dynamics of capillary flow. Phys. Rev. 17, 273283.
Wenzel, R. N. 1936 Resistance of solid surfaces to wetting by water. Ind. Engng Chem. 28, 988994.
Yi, J. W., Moon, M.-W., Ahmed, S. F., Kim, H., Cha, T.-G., Kim, H.-Y., Kim, S.-S. & Lee, K.-R. 2010 Long-lasting hydrophilicity on nanostructured Si-incorporated diamond-like carbon films. Langmuir 26, 1720317209.
MathJax
MathJax is a JavaScript display engine for mathematics. For more information see http://www.mathjax.org.

JFM classification

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed