In order for a material to dissolve, these same interactions need to be overcome, as the molecules are separated from each other and surrounded by the solvent.
In 1936 Joel Henry Hildebrand suggested the square root of the cohesive energy density as a numerical value indicating solvency behavior.
Materials with similar solubility parameters will be able to interact with each other, resulting in solvation, miscibility or swelling.
Its principal utility is that it provides simple predictions of phase equilibrium based on a single parameter that is readily obtained for most materials.
These predictions are often useful for nonpolar and slightly polar (dipole moment < 2 debyes[citation needed]) systems without hydrogen bonding.
The principal limitation of the solubility parameter approach is that it applies only to associated solutions ("like dissolves like" or, technically speaking, positive deviations from Raoult's law); it cannot account for negative deviations from Raoult's law that result from effects such as solvation or the formation of electron donor–acceptor complexes.