I Why does low surface energy imply hydrophobicity?

[voila]

I don't understand why materials with low surface energy are hydrophobic and viceversa. All I can find are quick phenomenological explanations that don't quite deal with the physical (microscopic) process going on.

Could anyone provide a good microscopic picture of why it is that way? What's the role of the bonds in the material and how does it interact with the liquid to make it (or not) spread?

 

[hilbert2]

It's just that if the surface energy between a solid and air is unusually small, it's more likely that replacing the air with a liquid will make the surface energy larger.

 

[voila]

@hilbert2 Say you have a metal surface. How are the bondings between the metal and the liquid?

 

[hilbert2]

@hilbert2 Say you have a metal surface. How are the bondings between the metal and the liquid?

They are not described in the same way how actual chemical bonds are described. There's a quite good explanation here how the interface energy depends on short- and long-range forces: http://www-f1.ijs.si/~rudi/sola/seminar_surface_tension.pdf .