4. Relationship between structure and performance

Almost all surfactants have a hydrophobic chain length between C8-C10 and C18, and non-ionic surfactants are no exception.

Chains shorter than C8-C10 are too short and too soluble in water to interact significantly with liquid or solid hydrophobic phases. The only hydrophilic groups with which these chains can be associated, while retaining interfacial properties, are amino, hydroxy or phosphate groups. These molecules have virtually no detergent, emulsifying or dispersant properties, but they can be used for their wetting effect or for the surface antistatic treatment of synthetic fibers. C3-C5 alcohols are cosurfactants in microemulsion systems.

Chain lengths longer than C18 are less commercially available and more expensive than C12-C18 chains. As a result, C20, C22 and even longer-chain derivatives have not attracted...