HLB Scale

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Entry by Andrew Capulli

HLB Scale: Hydrophilic-Lipophilic Balance

HLB Scale

HLB Scale is essentially a ranking of how hydrophilic an amphiphilic molecule (surfactant) is.

Developed by Griffin (1949), the HLB Scale ranks the tendency of a surfactant to be hydrophilic or hydrophobic (lipophilic). Since a surfactant molecule has both hydrophilic and hydrophobic portions (that's why its a surfactant!) Griffin developed a ranking system to determine 'how hydrophilic' and 'how hydrophobic' a surfactant is. Surfactants generally have hydrophobic hydrocarbon chains with hydrophilic branches or ends (this scale is for non-ionic surfactants). The HLB scale is very relative scale; the number values of the HLB Scale don't necessarily give insight into the properties of a surfactant, just their relative hydrophilicity compared to other surfactants. The That said, the HLB Scale is widely used in industry.

To summarize:

  • The HLB Scale ranges 1-20
  • Surfactants with higher HLB numbers (greater than 10) are more hydrophilic
  • Surfactants with lower HLB number (less than 10) are more hydrophobic (lipophilic)
  • Complete water solubility of a surfactant occurs at and HLB of approximately 7.3

Higher HLB Scale valued surfactants are more hydrophilic and thus are more water soluble. Similarly, lower HLB Scale valued surfactants are more lipophilic and thus more oil soluble. So, higher HLB surfactants will created oil-in-water emulsions and lower HLB surfactants will create water-in-oil emulsions:

HLB1.jpg

Often mixtures of surfactants are used to obtain a desired HBL number. To find the HLB number of a mixture of surfactants, the concentration of each surfactant is multiplied by its HLB number the sum of these number is divided by the total concentration of surfactant:

HLB2.jpg

An HLB calculator can be found at: http://www.al-nasir.com/www/PharmCalc/exec_calc.php?ID=hlb


To gain an idea of which surfactants to use in which situations, Uniqema (Surfactant company) uses the following guidelines for assigning surfactants to the following desired emulsions:

  • mixing unlike oils together
    • use surfactants with HLB’s of 1 to 3
  • making water-in-oil emulsions
    • use surfactants with HLB’s of 4 to 6
  • wetting powders into oils
    • use surfactants with HLB’s of 7 to 9
  • making self emulsifying oils
    • use surfactants with HLB’s of 7 to 10
  • making oil-in-water emulsions
    • use surfactant blends with HLB’s of 8 to16
  • making detergent solutions
    • use surfactants with HLB’s of 13 to 15
  • for solubilizing oils ( micro-emulsifying ) into water
    • use surfactant blends with HLB’s of 13 to 18


The HLB Scale can be related to a triboelectric series (see: Tribocharge). A triboelectric scale essentially ranks a material's likelihood of gaining electrons compared to other materials. Similarly, the HLB Scale ranks a surfactant's hydrophilicity relative to other surfactants.

Keyword in references:

[1] http://www.lotioncrafter.com/pdf/The_HLB_System.pdf

[2] http://www.al-nasir.com/www/PharmCalc/exec_calc.php?ID=hlb

[3] http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0032/0901b80380032332.pdf?filepath=oxysolvents/pdfs/noreg/110-00785.pdf&fromPage=GetDoc

Keyword in references:

Amphiphilic Crescent-Moon-Shaped Microparticles Formed by Selective Adsorption of Colloids