What are the applications of surfactants in pesticides?

In pesticide applications, direct use of the active ingredient is rare. Most formulations involve mixing pesticides with adjuvants and solvents to enhance efficacy and reduce costs. Surfactants are key adjuvants that maximize pesticide performance while lowering expenses, primarily through emulsification, foaming/defoaming, dispersion, and wetting effects. Their widespread use in pesticide formulations is well-documented. 

Surfactants improve interfacial tension between components in emulsions, creating uniform and stable dispersion systems. Their amphiphilic structure—combining hydrophilic and lipophilic groups—enables adsorption at oil-water interfaces. This reduces interfacial tension and minimizes the energy required for emulsion formation, thereby enhancing stability.

Dispersing pesticide active ingredients into water as micro-scale particles yields superior performance compared to other formulations. Emulsifiers directly influence the stability of pesticide emulsions, which in turn determines their effectiveness.

The stability varies with droplet size:

●  Particles <0.05 μm: Solubilized in water, highly stable.

●  Particles 0.05–1 μm: Mostly dissolved, relatively stable.

●  Particles 1–10 μm: Partial sedimentation or precipitation over time.

●  Particles >10 μm: Visibly suspended, highly unstable.

As pesticide structures evolve, highly toxic organophosphates are being replaced by safer, more efficient, and low-toxicity alternatives. Heterocyclic compounds—such as pyridine, pyrimidine, pyrazole, thiazole, and triazole derivatives—often exist as solids with low solubility in conventional solvents. This necessitates novel, high-efficiency, low-toxicity emulsifiers for their formulation.

China, a global leader in pesticide production and consumption, reported 2.083 million tons of technical-grade pesticide output in 2018. Rising environmental awareness has driven demand for higher-quality formulations. Consequently, research and application of eco-friendly, high-performance pesticides have gained prominence. High-quality surfactants, as critical components, play a pivotal role in advancing sustainable pesticide technologies.