https://doi.org/10.1351/goldbook.15196
Empirical scale (of \(0\!-\!20\)) used to classify surfactants and emulsifying agents.
Notes:
- The numerical value is determined by the expression (\({\rm{HLB}} = 20 M_{\rm{h}}/M\)) where \(M_{\rm{h}}\) is the molecular mass of the hydrophilic portion of the molecule, and \(M\) is the molecular mass of the whole molecule, giving a result on an arbitrary scale of \(0\!-\!20\).
- An HLB value of \(0\) corresponds to a completely hydrophobic molecule, while a value of \(20\) corresponds to a molecule made up completely of hydrophilic components.
- The more hydrophilic the surfactant the more it favors the formation of o/w over w/o emulsions.
Example: Ionic surfactants such as sodium lauryl sulfate have, e.g., an HLB of \(40\).