Question

What is the angle of contact for a liquid that does not wet the solid.

Answer 1

The wettability index that is the contact angle of the liquid with the solid depends on the surface energy of the material and if the surface energy is high then it prevent from any contact formation with the liquid and the contact angle is about${180}^{\circ }$.The contact angle of the non wetting liquid remain between ${90}^{\circ }-{180}^{\circ }$.This happens when the adhesive forces are more than the cohesive forces.