Dynamic Wetting Droplet Tap Dance and Leidenfrost Effect

7 Dynamic Wetting Droplet Tap Dance and Leidenfrost Effect 

The alternatively charging of the encapsuled salty droplet may alternate the repulsion and the attraction between the droplet and the hydrophobic surface that is highly elastic and polarized. This charge induction and the interface interaction might contribute to the tap dance of the droplet. 

This is because at temperatures above the Leidenfrost point, and the bottom part of the water droplet vaporizes immediately in contact with the hot plate. The resulting gas suspends the rest of the water droplet just above it, preventing any further direct contact between the liquid water and the hot plate. As steam has much poorer thermal conductivity, and further heat transfer between the pan and the droplet is slowed down dramatically. This also results in the drop being able to skid around the pan on the layer of gas just under it. 

Liquid-vapor phase transition at the contacting point will eject molecules with momentum, which applies an impulse to the droplet. The direction of the impulse is subject to contacting conditions. The parallel component of the impulse will push the droplet upward the incline, and the perpendicular component will separate the pan and the droplet. Theoretical formulation of the Leidenfrost effect, particularly the upward movement of the droplet, from the perspective of momentum and impulse could be interesting. 

Water evaporates more easily at higher temperatures under the less saturated vapour pressure than the otherwise because both heating and less-saturated vapoiu pressure lengthens and soften the 0 H bond. The 0 H bond energy determines the dissociation energy for molecular evaporation. 

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