Leidenfrost effect

Leidenfrost effect

It is a physical phenomenon, where the volatile liquid drops are in levitation upon close contact with the hot surface. The hotness of the surface is significantly higher than the boiling point of the liquid. An insulating vapor layer is developed by the liquid on the deposited surface which inhibits the drops to evaporate and the generated repulsive force propels the random movement of the liquid drop. It was first proposed by J. G. Leidenfrost.

Features:

1. A lifetime in the order of minute scale
2. self-propelled
3. Absence of friction
4. Rich dynamics  
5. Glides at a slight inclination  
6. Drop deformation     

Inverse Leidenfrost effect

An inverse Leidenfrost effect is observed when the ambient temperature liquid drops are deposited on liquid nitrogen, which maintains a cryogenic environment as the boiling temperature of liquid nitrogen is -196 °C. The rate of evaporation of liquid nitrogen is so fast that any liquid at ambient temperature approaches to nitrogen bath levitates the drops instantly.

Features:

1. The time scale in the tens of minutes
2. Self-propelled
3. Absence of friction
4. Counterintuitive dynamics
5. Gliding in straight lines
6. Drop sinking

Application:  Biological materials (Cells, Proteins) transportation in the biomedical field.

pnas.org/content/116/4/1174