A 'Chaotropic agent' is an agent which causes molecular structure to be disrupted; in particular, those formed by noncovalent forces such as
hydrogen bonding, Van der Waals interactions, and the
hydrophobic effect. Often structural features, as detected by means such as
circular dichroism can be titrated in a chaotrope concentration-dependent fashion.
The most commonly used chaotropes are 6~8M
urea and 6M
guanidinium chloride, with urea being an uncharged molecule and guanidinium chloride being a hydrochloride salt.
High generic salts can have chaotropic properties, by shielding charges and preventing the stabilization of salt bridges. Hydrogen bonding is stronger in nonpolar media, so salts, which increase the
dipole moment of the
solvent, can also destabilize hydrogen bonding.
See also
★
Kosmotropic