A wealth of non-ionic 0/W emulsifiers is available. These are mainly PEG derivatives such as êthoxylates or PEG esters. Typical O/W emulsifiers are :
• ethoxylated fatty a!coho
• PEG esters of fatty acids
• ethoxylated sorbitan esters
• ethoxylated monoglycerides
• ethoxylated castor-oil derivatives.
The degree of ethoxylation determines the primary properties of that part of the molecule that results in the HLB classification. Good 0/W emulsifiers can be found in the HLB range between 8 and 18. However, the type of hydrophobic moiety is also very important for the stability of the emulsions. Contrary to anionic emulsifiers, the non-ionics are unaffected by changes in pH and, in the case of pure ethers, they can also be used at extreme pH values.
Following the trend towards more ‘natural’ cosmetics, trials have been made in order to replace the E0 chain by polyglycerol or sugars but up till now it has not been possible to reach high HLB values.
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