Hydrophilic-Lipophilic HLB Values of Emulsifiers

W/O emulsions are formed by using HLB values between 3.6 and 6, thus suggesting that emulgators that are soluble in the oil phase are generally used. O/W emulsions need HLB values around 8 to 18. This is only a very general observation it must be noted that HLB values alone do not determine emulsion type. Other parameters, such as temperature, properties of the oil phase, and electrolytes in the aqueous phase also have their effect. However, HLB values have no relation to the degree 

HLB Values of Different Emulsifiers Commonly Used in Emulsions 

Very low solubility Low solubility Soluble High solubility 

HLB Values of Some Typical Surface-Active Agents 

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, KD, of the emulsifier in the oil and water phases  

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