In physical chemistry, the van der Waals' forces (or van der Waals' interaction), named after Dutch scientist Johannes Diderik van der Waals, are the residual attractive or repulsive forces between molecules or atomic groups that do not arise from a covalent bond, or ionic bonds.[1] The resulting van der Waals forces can be attractive or repulsive.[2]
The term includes:
force between permanent dipoles (Keesom force)
force between a permanent dipole and a corresponding induced dipole (Debye force)
force between instantaneously induced dipoles (London dispersion force).
It is also sometimes used loosely as a synonym for the totality of intermolecular forces.[citation needed] Van der Waals forces are relatively weak compared to covalent bonds, but play a fundamental role in fields as diverse as supramolecular chemistry, structural biology, polymer science, nanotechnology, surface science, and condensed matter physics. Van der Waals forces define many properties of organic compounds, including their solubility in polar and non-polar media.
In low molecular weight alcohols, the hydrogen-bonding properties of their polar hydroxyl group dominate other weaker van der Waals interactions. In higher molecular weight alcohols, the properties of the nonpolar hydrocarbon chain(s) dominate and define the solubility. Van der Waals forces quickly vanish at longer distances between interacting molecules.
