Emulsions, Microemulsions, and Lyotropic Liquid Crystals - Surface and Colloid Chemistry: Principles and Applications - page 177

table 9.3
hlb values of Some typical
Surface-active agents

Surface-active agents hlb

Na-lauryl sulfate 40

Na-oleate 18

Tween80 (sorbitan monooleate EO20) 15

Tween81 (sorbitan monooleate EO6) 10

Ca-dodecylbenzene sulfonate 9

Sorbitan monolaurate 9

Soya lecithin 0.8

Sorbitan monopalmiate 0.7

Glycerol monolaurate 5

Sorbitan monostearate 0.5

Span80 (sorbitan monooleate) 4

Glycerol monostearate 4

Glycerol monooleate 3

Sucrose distearate 3

Cetyl alcohol 1

Oleic acid 1

of emulsion stability. The HLB values of some surface-active agents are given in
Table 9.3.
HLB values decrease as the solubility of the surface-active agent decreases in
water . Solubility of cetyl alcohol in water (at 25°C) is less than a milligram per liter.
It is thus obvious that, in any emulsion, cetyl alcohol will be present mainly in the oil
phase, while SDS will be mainly found in the water phase. Empirical HLB values
are found to have significant use in emulsion technology applications. It was shown
that HLB is related, in general, to the distribution coefficient, K D , of the emulsifier
in the oil and water phases:

K D = C(water)/C(oil) (9.1)

where C(water) and C(oil) are the equilibrium molar concentrations of the emulsifier in
the water and oil phases, respectively. Based on this definition of K D , it is found that

(HLB − 7) = 0.36 ln (K D ) (9.2)

The relation between HLB and emulsion stability and structure could be suggested
based on this thermodynamic relation. HLB values can also be estimated from the
structural groups of the emulsifier (Table 9.4).
Food emulsifiers have found extensive application in industry. Therefore, they
must satisfy special requirements of the food industry. For example, their toxicity