Hydrophil

Hydrophil means water attracting.

A surface is hydrophil when the surface energy is above the surface tension of water which is 72 mN/m. In this case water molecules are more attracted by the molecules of the surface than by the water molecules in their neighbourhood. In consequence a water volume is spreaded flat with the surface instead of remaining in form of spherical shaped water drops which are not wetting the surface.

Hydrophility can be desired for good wetting  and good adhesion of substances. A surface can be modified to become hydrophilic by plasma activation or by plasma coating. When non polar plastic surfaces are plasma activated polar groups are generated.

The oposite of hydrophil is hydrophob.

Hydrohobic and hydrophylic surface treatment of fabrics