Nonionic or Neutral Surfactants

Nonionic surfactants are a class of surfactants that do not carry any charge, unlike anionic or cationic surfactants. These surfactants have both hydrophilic (water-loving) and hydrophobic (water-repelling) parts, but they do not dissociate into ions in solution. Nonionic surfactants are particularly valued for their mildness, stability, and compatibility with the skin, which makes them ideal for use in cosmetic, pharmaceutical, and food formulations.

Chemical Composition and Structure

Nonionic surfactants are composed of molecules that contain hydrophilic groups (such as alcohols or sugars) and hydrophobic groups (such as fatty acid chains or alkyl groups), but they lack ionic groups. Some of the most common types of nonionic surfactants include:

• Alkylpolyglycosides: Derived from glucose and fatty alcohols, these are very mild and well-tolerated by the skin.
• Alkylamides: Formed from the reaction of fatty acids with amines, often used as co-surfactants.
• Polyethylene glycol esters (PEG): Esters made from the reaction of alcohols and polyethylene glycol, mainly used as emulsifiers or solubilizers.
• Sorbitan esters: Derived from sorbitol, these are used as emulsifiers in various cosmetic products.

Physical Properties

• Solubility: Nonionic surfactants are soluble in both water and oils, allowing them to reduce surface tension and facilitate the mixing of water and oils.
• Stability: They are generally more stable than ionic surfactants and maintain their effectiveness across a broad pH range.
• Skin compatibility: Nonionic surfactants are less irritating to the skin compared to ionic surfactants, making them ideal for delicate products such as shampoos and cleansers for sensitive skin.

Applications

Cosmetics

• Shampoos and skin cleansers: Nonionic surfactants are commonly used in shampoos and cleansers for their ability to remove impurities without damaging or drying the skin.
• Creams and lotions: They are used as emulsifiers to blend water and oils in cosmetic formulations, improving the texture and stability of the product.
• Facial and body products: Due to their mildness, they are also found in products for facial and body care, such as moisturizers, masks, and skin treatments.

Food Industry

• Emulsifiers: Nonionic surfactants, like sorbitan esters, are used as emulsifiers in foods to improve the texture and stability of products such as sauces, mayonnaise, and ice cream.
• Additives for texture improvement: They are added to food products to improve mouthfeel and prevent ingredient separation.

Pharmaceuticals

• Pharmaceutical formulations: Nonionic surfactants are used in topical medications like creams and ointments, where they act as solubilizers and emulsifiers.
• Oral solutions: They are also used in oral medications to improve the solubility and uniform distribution of active ingredients.

Environmental and Safety Considerations

• Biodegradability: Nonionic surfactants, especially those derived from natural sources like alkylpolyglycosides, are generally biodegradable and less harmful to the environment compared to synthetic alternatives.
• Safety profile: Nonionic surfactants are considered safe for use in a wide range of personal care products, including those for sensitive skin, due to their mildness. However, it is important to follow recommended concentrations to avoid unwanted reactions.

Of all the surfactants are those with the least aggressiveness on the skin.

Nonionic surfactant studies