Definition of Hydrophile-Lipophile Balance Scale
- The HLB scale is a numerical system that indicates the balance between the hydrophilic and lipophilic portions of a surfactant molecule.
- Scale Range: 0 (completely lipophilic) to 20 (completely hydrophilic).
Calculation of Hydrophile-Lipophile Balance Scale
- For nonionic surfactants:
-
$\text{HLB} = 20 \times \frac{M_{\text{hydrophilic}}}{M_{\text{total}}}$
-
- where:
- is the molecular mass of the hydrophilic portion.
- is the total molecular mass of the surfactant.
Applications
- Emulsion Type Determination:
- O/W Emulsions: Surfactants with HLB values of 8-18.
- W/O Emulsions: Surfactants with HLB values of 3-6.
- Formulation Optimization: Selecting appropriate surfactants for desired properties.
- Solubilizers and Detergents: High HLB surfactants are effective solubilizers.
Blending Surfactants
- Surfactants can be blended to achieve a desired HLB value.
- Equation:
-
$\text{HLB}_{\text{blend}} = f_A \times \text{HLB}_A + f_B \times \text{HLB}_B$
-
- where:
- fA and fB are the weight fractions of surfactants A and B.
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