Hydrophile-Lipophile Balance Scale

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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