Skip to main content
×
×
Home

Probing the nanoscale: the first contact of an impacting drop

  • E. Q. Li (a1), I. U. Vakarelski (a1) and S. T. Thoroddsen (a1)
Abstract

When a drop impacts onto a solid surface, the lubrication pressure in the air deforms its bottom into a dimple. This makes the initial contact with the substrate occur not at a point but along a ring, thereby entrapping a central disc of air. We use ultra-high-speed imaging, with 200 ns time resolution, to observe the structure of this first contact between the liquid and a smooth solid surface. For a water drop impacting onto regular glass we observe a ring of microbubbles, due to multiple initial contacts just before the formation of the fully wetted outer section. These contacts are spaced by a few microns and quickly grow in size until they meet, thereby leaving behind a ring of microbubbles marking the original air-disc diameter. On the other hand, no microbubbles are left behind when the drop impacts onto molecularly smooth mica sheets. We thereby conclude that the localized contacts are due to nanometric roughness of the glass surface, and the presence of the microbubbles can therefore distinguish between glass with 10 nm roughness and perfectly smooth glass. We contrast this entrapment topology with the initial contact of a drop impacting onto a film of extremely viscous immiscible liquid, where the initial contact appears to be continuous along the ring. Here, an azimuthal instability occurs during the rapid contraction at the triple line, also leaving behind microbubbles. For low impact velocities the nature of the initial contact changes to one initiated by ruptures of a thin lubricating air film.

Copyright
Corresponding author
Email address for correspondence: sigurdur.thoroddsen@kaust.edu.sa
References
Hide All
Beilharz, D., Guyon, A., Li, E. Q., Thoraval, M.-J. & Thoroddsen, S. T. 2015 Antibubbles and fine cylindrical sheets of air. J. Fluid Mech. 779, 87115.
Bouwhuis, W., Hendrix, M. H. W., van der Meer, D. & Snoeijer, J. H. 2015 Initial surface deformations during impact on a liquid pool. J. Fluid Mech. 771, 503519.
Bouwhuis, W., van der Veen, R. C. A., Tran, T., Keij, D. L., Winkels, K. G., Peters, I. R., van der Meer, D., Sun, C., Snoeijer, J. H. & Lohse, D. 2012 Maximal air bubble entrainment at liquid-drop impact. Phys. Rev. Lett. 109, 264501.
Chandra, S. & Avedisian, C. T. 1991 On the collision of a droplet with a solid surface. Proc. R. Soc. Lond. A 432, 1341.
Crooks, J., Marsh, B., Turchetta, R., Taylor, K., Chan, W., Lahav, A. & Fenigstein, A. 2013 Kirana: a solid-state megapixel uCMOS image sensor for ultrahigh speed imaging. Proc. SPIE 8659, 865903.
Driscoll, M. M. & Nagel, S. R. 2011 Ultrafast interference imaging of air in splashing dynamics. Phys. Rev. Lett. 107, 154502.
Duchemin, L. & Josserand, C. 2011 Curvature singularity and film-skating during drop impact. Phys. Fluids 23, 091701.
Hicks, P. D., Ermanyuk, E. V., Gavrilov, N. V. & Purvis, R. 2012 Air trapping at impact of a rigid sphere onto a liquid. J. Fluid Mech. 695, 310320.
Hicks, P. D. & Purvis, R. 2010 Air cushioning and bubble entrapment in three-dimensional droplet impacts. J. Fluid Mech. 649, 135163.
Hicks, P. D. & Purvis, R. 2013 Liquid–solid impacts with compressible gas cushioning. J. Fluid Mech. 735, 120149.
Kolinski, J. M., Mahadevan, L. & Rubinstein, S. M. 2014 Drops can bounce from perfectly hydrophilic surfaces. Eur. Phys. Lett. 108, 24001.
Kolinski, J. M., Rubinstein, S. M., Mandre, S., Brenner, M. P., Weitz, D. A. & Mahadevan, L. 2012 Skating on a film of air: drops impacting on a surface. Phys. Rev. Lett. 108, 074503.
Korobkin, A. A., Ellis, A. S. & Smith, F. T. 2008 Trapping of air in impact between a body and shallow water. J. Fluid Mech. 611, 365394.
Lee, J. S., Weon, B. M., Je, J. H. & Fezzaa, K. 2012 How does an air film evolve into a bubble during drop impact? Phys. Rev. Lett. 109, 204501.
Li, E. Q., Al-Otaibi, S., Vakarelski, I,. U. & Thoroddsen, S. T. 2014 Satellite formation during bubble transition through an interface between immiscible liquids. J. Fluid Mech. 744, R1.
Li, E. Q. & Thoroddsen, S. T. 2015 Time-resolved imaging of a compressible air disc under a drop impacting on a solid surface. J. Fluid Mech. 780, 636648.
Liu, Y., Tan, P. & Xu, L. 2013 Compressible air entrapment in high-speed drop impacts on solid surfaces. J. Fluid Mech. 716, R9.
Mandre, S. & Brenner, M. P. 2012. The mechanism of a splash on a dry solid surface. J. Fluid. Mech. 690, 148172.
Mandre, S., Mani, M. & Brenner, M. P. 2009 Precursors to splashing of liquid droplets on a solid surface. Phys. Rev. Lett. 102, 134502.
Mani, M., Mandre, S. & Brenner, M. P. 2010 Events before droplet splashing on a solid surface. J. Fluid. Mech. 647, 163185.
Palacios, J., Hernández, J., Gómez, P., Zanzi, C. & López, J. 2012 On the impact of viscous drops onto dry smooth surfaces. Exp. Fluids 52, 14491463.
de Ruiter, J., Lagraauw, R., van den Ende, D & Mugele, F. 2015 Wettability-independent bouncing on flat surfaces mediated by thin air films. Nat. Phys. 11, 4853.
de Ruiter, J., Oh, J. M., van den Ende, D. & Mugele, F. 2012 Dynamics of collapse of air films in drop impact. Phys. Rev. Lett. 108, 074505.
Smith, F. T., Li, L. & Wu, G. X. 2003 Air cushioning with a lubrication/inviscid balance. J. Fluid Mech. 482, 291318.
Style, R. W., Hyland, C., Boltyanskiy, R., Wettlaufer, J. S. & Dufresne, E. R. 2013 Surface tension and contact with soft elastic solids. Nat. Commun. 4, 2728.
Thoroddsen, S. T., Etoh, T. G., Takehara, K., Ootsuka, N. & Hatsuki, Y. 2005 The air-bubble entrapped under a drop impacting on a solid surface. J. Fluid Mech. 545, 203212.
Thoroddsen, S. T. & Sakakibara, J. 1998 Evolution of the fingering pattern of an impacting drop. Phys. Fluids 10, 13591374.
Thoroddsen, S. T., Takehara, K. & Etoh, T. G. 2010 Bubble entrapment through topological change. Phys. Fluids 22, 051701.
Thoroddsen, S. T., Thoraval, M.-J., Takehara, K. & Etoh, T. G. 2012 Micro-bubble morphologies following drop impacts onto a pool surface. J. Fluid Mech. 708, 469479.
van der Veen, R. C. A., Tran, T., Lohse, D. & Sun, C. 2012 Direct measurements of air layer profiles under impacting droplets using high-speed color interferometry. Phys. Rev. E 85, 026315.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×
MathJax

JFM classification

Type Description Title
UNKNOWN
Supplementary materials

Li et al. supplementary material
Supplementary figure

 Unknown (3.7 MB)
3.7 MB
VIDEO
Movies

Li et al. supplementary movie
Drop impact on 20 million cSt silicone oil, for conditions in Figure 4(a). Recording frame rate is 5 million fps. Horizontal extent: 0.86 mm. Vertical extent: 0.72 mm.

 Video (3.7 MB)
3.7 MB
UNKNOWN
Supplementary materials

Li et al. supplementary material
Supplementary material

 Unknown (2.6 MB)
2.6 MB
VIDEO
Movies

Li et al. supplementary movie
Drop impact on Fisher microscope slide, for conditions in Figure 3(c). Recording frame rate is 5 million fps. Horizontal extent: 0.32 mm. Vertical extent: 0.43 mm.

 Video (4.5 MB)
4.5 MB
VIDEO
Movies

Li et al. supplementary movie
Drop impact on 20 million cSt silicone oil, for conditions in Figure 4(b). Recording frame rate is 2 million fps. Horizontal extent: 0.67 mm. Vertical extent: 0.58 mm.

 Video (6.1 MB)
6.1 MB
VIDEO
Movies

Li et al. supplementary movie
Drop impact on 20 million cSt silicone oil, for conditions in Figure 4(b). Recording frame rate is 2 million fps. Horizontal extent: 0.67 mm. Vertical extent: 0.58 mm.

 Video (6.0 MB)
6.0 MB
VIDEO
Movies

Li et al. supplementary movie
Rupture of the thin air-film between a sliding water drop impacting on 20 million cSt silicone oil, for conditions in Figure 5. Recording frame rate is 5 million fps. Horizontal extent: 0.52 mm. Vertical extent: 0.43 mm.

 Video (6.0 MB)
6.0 MB
VIDEO
Movies

Li et al. supplementary movie
Drop impact on mica surface for conditions in Figure 3(b). Recording frame rate is 5 million fps. Horizontal extent: 0.67 mm. Vertical extent: 0.67 mm.

 Video (4.4 MB)
4.4 MB
VIDEO
Movies

Li et al. supplementary movie
Rupture of the thin air-film between a sliding water drop impacting on 20 million cSt silicone oil, for conditions in Figure 5. Recording frame rate is 5 million fps. Horizontal extent: 0.52 mm. Vertical extent: 0.43 mm.

 Video (5.4 MB)
5.4 MB
VIDEO
Movies

Li et al. supplementary movie
Ring of microbubbles produced by a water drop impacting on Corning microscope glass slide, for conditions in Figure 3(a). Recording frame rate is 5 million fps. Horizontal extent: 0.96 mm. Vertical extent: 0.80 mm.

 Video (5.8 MB)
5.8 MB
VIDEO
Movies

Li et al. supplementary movie
Drop impact on 20 million cSt silicone oil, for conditions in Figure 4(a). Recording frame rate is 5 million fps. Horizontal extent: 0.86 mm. Vertical extent: 0.72 mm.

 Video (4.9 MB)
4.9 MB
VIDEO
Movies

Li et al. supplementary movie
Drop impact on mica surface for conditions in Figure 3(b). Recording frame rate is 5 million fps. Horizontal extent: 0.67 mm. Vertical extent: 0.67 mm.

 Video (4.2 MB)
4.2 MB
VIDEO
Movies

Li et al. supplementary movie
Drop impact on Fisher microscope slide, for conditions in Figure 3(c). Recording frame rate is 5 million fps. Horizontal extent: 0.32 mm. Vertical extent: 0.43 mm.

 Video (4.3 MB)
4.3 MB
VIDEO
Movies

Li et al. supplementary movie
Ring of microbubbles produced by a water drop impacting on Corning microscope glass slide, for conditions in Figure 3(a). Recording frame rate is 5 million fps. Horizontal extent: 0.96 mm. Vertical extent: 0.80 mm.

 Video (7.3 MB)
7.3 MB

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