Super-vortex Skating
A popular charity collection box is a coin vortex funnel – coins go round and round before dropping through the hole. When a jet of water is used on an ordinary funnel it quickly goes down the plug, as shown in video 1. In video 2, a jet of water is shown on a funnel with a superhydrophobic surface. The jet breaks up into droplets and goes round many more times than on an ordinary surface.
We can observe a jet of water flowing around a funnel with no coating:
We can then compare this to when a jet of water flows around a funnel coated with a super-hydrophobic surface:
The result is clearly very different!