Folding surfaces: Capillary Origami

The word “hydrophobic” means fear of water. Teflon is the most hydrophobic material that chemistry can create (as evidenced by its use as a non-stick coating for cooking pans). Therefore, we would expect water and Teflon to want to avoid each other. However, when a droplet of water touches a thin sheet of Teflon, the Teflon wraps itself around the water droplet, as seen in the video below.

A droplet of water coming into contact with a thin sheet of Teflon. Video provided courtesy Prof. Tom McCarthy.

It seems that even Teflon prefers to cling to the surface of water rather than remain in contact with air.

Spontaneous wrapping of a droplet of water by Teflon is a form of Capillary Origami.

It is only when we make the Teflon surface superhydrophobic that the wrapping effect is suppressed (see lower image sequence below).

Different stages of drop deposition

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