Surface Energy

On the RHS, the first term is the apolar (or nonpolar) component and the latter is the polar component.

1. Lifshitz-vab der Waals (LW) interactions

The LW component has contribution from the van der Waals (or dispersion) forces. These forces are always attractive in nature.

2. Acid-Base (A-B) interactions

The A-B component has contributions from the following interactions.

(i) Hydrogen bonding

This occurs in the case of Bronsted acid and bases. A Bronsted acid (or H⁺ donor) is a compound having the ability to donate a proton (H⁺) e.g. CHCl₃. And a Bronsted base (or H+ acceptor) is a compound having the ability to accept a proton. e.g. ketones. The proton donor and acceptor capabilities are measured by the magnitude of and , respectively.

Both characteristics might be present within the molecule leading to H-bonding with its own molecules.