At present, surfactants are used not only in herbicides but in all pesticide formulations. In 1993, the global consumption of surfactants for pesticides was approximately 230,000 tons, accounting for 3.3% of the total surfactant usage. In the United States, the sales value of surfactants for pesticides made up about 6% of its pesticide market. Half of all pesticide formulations in 1992 employed surfactants, most of which were used in herbicides. In China, the consumption of surfactants for pesticides stood at around 40,000 tons, with roughly one-third serving as emulsifiers.
Surfactants can convert unmanageable technical-grade pesticides into applicable pesticide formulations. As a pesticide adjuvant, they not only enhance the application efficacy of pesticides but also reduce pesticide dosage, alleviate the environmental impact of pesticides, and deliver substantial benefits to agricultural production. However, since pesticides are special chemicals with strong biological activity, and their control targets, protected objects, and environmental conditions are highly complex, surfactants in pesticides must be selected and formulated according to the properties and characteristics of the technical materials, while also taking into account the effects of the surfactants themselves on target organisms.
The following focuses on introducing the usage guidelines for three types of surfactants.
By utilizing the micellar action of surfactants, the solubility of poorly soluble technical materials in solvents is significantly increased, which is known as solubilization. Surfactants with an HLB value of 15–18 can serve as solubilizers, but solubilization only occurs when the concentration of the solubilizer exceeds the critical micelle concentration. At this point, the poorly soluble drug is encapsulated or adsorbed inside the micelles by the lipophilic groups of the solubilizer, while the hydrophilic groups of the solubilizer remain in the water, thus enabling non-polar drugs to dissolve in water.
Dispersants can hinder or prevent the aggregation of solid or liquid particles in a dispersion system and maintain their uniform dispersion for an extended period. Dispersants adsorb at the oil-water interface or on the surface of solid particles, forming an electric charge or steric hindrance potential barrier around the particles, which helps prevent pesticide particles from re-aggregating during formulation and storage. Dispersants used are generally anionic surfactants with multiple rings, such as sodium salts of alkylnaphthalene sulfonates, naphthalene sulfonic acid-formaldehyde condensates, and lignosulfonates. In contrast, polymeric dispersants (such as sodium polycarboxylate) are particularly important in the preparation of aqueous suspensions due to their adsorption properties, as well as their ability to charge dispersed particles and create a large steric potential barrier.
Mixed formulations are popular among users due to their convenience and ability to ensure the correct dosage of various pesticide ingredients, while avoiding the inhomogeneity commonly encountered in conventional tank mixing. Such formulations are suspension-based mixed dispersions prepared using a water-insoluble solid pesticide and a water-insoluble liquid pesticide with water as the medium and surfactants as auxiliary agents, and can generally be regarded as a combination of SC and EW. Commonly used surfactants mainly include emulsifiers, dispersants, thickeners, and others. This formulation type not only suffers from the flocculation of particles and oil droplets inherent in SC and EW formulations, but also makes it essential to conduct various cold and hot storage tests over a wide range of conditions.
Post time: Apr-09-2026