Wed March 17th 2021
16:00 – 17:00
Seminar When honey moves faster than water
Matilda Backholm


The viscosity of a fluid is well known to limit its flow: the more viscous a droplet, the slower it moves [1]. Here, we show that this intuitive rule breaks down in a confined liquid-repellent geometry. A gravity-driven, highly viscous glycerol droplet placed in a sealed superhydrophobic capillary moves more than 10 times faster than a low-viscosity water droplet [2]. This anomalous, viscosity-enhanced droplet motion is caused by a viscosity-suppressed deformation of the droplet-air interface. We find that the air film (plastron) trapped within the micro/nanostructure of the superhydrophobic coating plays an interesting and important role in controlling fluid flow beyond a mere reduction in contact area and friction.

[1] T. Mouterde, P. S. Raux, C. Clanet, and D. Quéré, Proc. Natl. Acad. Sci. USA 116 (2019).
[2] M. Vuckovac, M. Backholm, J. V. I. Timonen, and R. H. A. Ras, Science Advances 6 (2020).
Go back to the agenda.

The 10th Complex Motion in Fluids 2021
21st Internation Couette–Taylor Workshop
Max Planck Gesellschaft
Centre for Scientific Computing