that is required to build an area of a particular surface. Another way to view the surface energy is to relate it to the work required to cleave a bulk sample, creating two surfaces. If the new surfaces are identical, the surface energy ? of each surface is equal to half the work of cleavage, W: ? = (1/2)W₁₁.

If the surfaces are unequal, the Young-Dupré equation applies:W₁₂ = ?₁ + ?₂ - ?₁₂, where ?₁