Van der waals force & hydrophobic effect

Park, Ho-Min

Van der Waals forces are electrostatic forces. They operate not only between polar molecules but also between electrically neutral atoms and molecules. This is because the movement of electrons in the outer shell of the atoms temporarily leads to charge displacements – and to so-called polarization. Charged areas with different signs are then attracted to one another – and therefore ensure an attraction between two atoms, even if these are electrically neutral overall. The van der Waals force is an electromagnetic interaction between correlated fluctuating charges on two electrically neutral surfaces. As the surfaces approach more closely, the force increases as fluctuations of shorter and shorter length scale come into play, but ultimately the force will saturate when the surfaces are so close that the even shortest wavelength charge fluctuations are included.

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