Nonionic surfactants are a category of surface-active agents that do not dissociate in aqueous solution and carry no electrical charge on their hydrophilic groups. Their hydrophilicity primarily derives from polar groups such as polyoxyethylene chains, hydroxyl groups, or amide groups that form hydrogen bonds with water molecules. These surfactants exhibit exceptional hardness resistance, outstanding emulsifying and dispersing capabilities, and excellent compatibility with other surfactant types. Common nonionic surfactants include fatty alcohol polyoxyethylene ethers, alkylphenol ethoxylates, fatty acid sorbitan esters (Spans), and their polyoxyethylene derivatives (Tweens). They are widely used in detergents, cosmetics, pesticide emulsification, textile processing, and food industry applications. Their performance is significantly influenced by temperature, with some varieties precipitating and losing efficacy above their cloud point. Due to low irritancy and good biodegradability, they hold important positions in environmentally friendly products.