Namely
PPG-5-Ceteth-20 is a synthetic molecule used in cosmetics as a very mild emulsifier and nonionic surfactant. Nevertheless, the ingredient is very unecological given its manufacturing process (ethoxylation) and low biodegradability.
Its functions (INCI)
Emulsifying : Promotes the formation of intimate mixtures between immiscible liquids by modifying the interfacial tension (water and oil)
Surfactant : Reduces the surface tension of cosmetics and contributes to the even distribution of the product when it is used