Surfactants are amphiphilic compounds used to lower the surface and interfacial tension between different substances, such as oil and water. They are classified into four major categories based on the charge of the hydrophilic head group: anionic, cationic, amphoteric, and non-ionic. Among these, non-ionic surfactants do not carry a net charge, making them less reactive with water hardness ions and compatible with other types of surfactants.
Non-ionic surfactants are typically composed of ethoxylated alcohols, alkylphenol ethoxylates, or block copolymers. They are widely used for their:
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Low foaming properties
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Excellent detergency and emulsifying ability
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Stability in acidic and alkaline environments
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Reduced skin and material irritation compared to ionic surfactants
However, traditional non-ionic surfactants—especially those based on alkylphenol ethoxylates—have raised environmental concerns due to their slow biodegradability and the potential formation of endocrine-disrupting byproducts.