Surface Energy
The excess thermodynamic energy at the surface of a material relative to its interior bulk, caused by disrupted, incomplete atomic bonds.
Governing formula
γ = dW / dA
SI unit
J/m² or N/m
In depth
Interior bulk atoms are surrounded symmetrically by nearest neighbors, whereas surface atoms lack outward bonding partners. Materials spontaneously minimize surface energy by lowering surface area or adsorbing molecules.
Examples in the real world
Liquid contact angle wetting behavior and grain boundary energy driving grain growth during metal annealing.