Synopsis: Stop! Slippery water

Ridges and dips provide control of how a drop of liquid, despite extreme mobility, moves on a very hot surface.

When water drops skitter across a griddle, cooks know that it is hot enough to pour on the pancake batter. These “Leidenfrost” drops are separated from the surface by a cushion of vapor that greatly decreases their resistance to motion.

In a paper in Physical Review Letters, Guillaume Dupeux at CNRS ESPCI in Paris, France, and colleagues tell us how to use textured surfaces to control and even immobilize these drops, stopping them within centimeters instead of meters. On a ridged surface, the drops hit the ridges’ sides, losing kinetic energy on impact. Also, drops often fall partly into the grooves and must overcome the resultant potential energy loss in order to continue moving along the surface. Motion stops abruptly when a drop does not have enough kinetic energy to climb the next ridge.

It is possible that water may experience similar effects on unheated superhydrophobic surfaces, on which drops also make ultramobile pearls that could be controlled or trapped using such textures. – Jane Throwe


Features

More Features »

Announcements

More Announcements »

Subject Areas

Fluid Dynamics

Previous Synopsis

Magnetism

Balance excludes magnetism

Read More »

Next Synopsis

Related Articles

Focus: Nanochannel Could Separate Mixed Fluids
Fluid Dynamics

Focus: Nanochannel Could Separate Mixed Fluids

Calculations show that capillary forces affecting a fluid mixture flowing through a nanochannel could be used to separate the mixture. Read More »

Viewpoint: Superfluids Hit the Street
Atomic and Molecular Physics

Viewpoint: Superfluids Hit the Street

A flow pattern dubbed the von Kármán vortex street, which is renowned for its aesthetic beauty and extreme power, has been created in a superfluid. Read More »

Synopsis: Wetting Matters When Emptying a Tank
Fluid Dynamics

Synopsis: Wetting Matters When Emptying a Tank

The speed at which water drains out of a tank depends on the affinity of water with the outside surface of the orifice through which it drains.   Read More »

More Articles