Why does low surface energy imply hydrophobicity?

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SUMMARY

Materials with low surface energy exhibit hydrophobicity due to the interactions between the solid's surface and the liquid. When the surface energy between a solid and air is low, replacing air with a liquid increases the surface energy, leading to poor wetting. The bonding characteristics between the solid (such as metals) and the liquid play a crucial role in determining the extent of spreading. Understanding the interface energy, influenced by short- and long-range forces, is essential for grasping these phenomena.

PREREQUISITES
  • Understanding of surface energy concepts
  • Familiarity with intermolecular forces
  • Knowledge of chemical bonding in solids
  • Basic principles of liquid-solid interactions
NEXT STEPS
  • Research the role of intermolecular forces in surface energy
  • Study the principles of wetting and spreading coefficients
  • Explore the microscopic interactions between metals and liquids
  • Examine the effects of surface treatments on hydrophobicity
USEFUL FOR

Materials scientists, chemists, and engineers interested in surface properties and hydrophobic materials will benefit from this discussion.

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