Introduction
In the field of agricultural crop protection, plant protection oil formulations-i.e., pesticide emulsifiable concentrates or aqueous emulsions-serve as the critical carrier for delivering active ingredients to target crops. Emulsifiers, as the core adjuvants, determine whether the spray liquid can form a stable emulsion, spread uniformly on leaf surfaces, and allow active ingredients to penetrate efficiently.
Among the numerous available emulsifier options, PGE (Polyglycerol Esters of Fatty Acids) and DATEM (Diacetyl Tartaric Acid Esters of Mono- and Diglycerides) are two types that have attracted considerable attention. PGE has already emerged as a prominent player in the pesticide adjuvant field, leveraging its unique molecular structure and superior interfacial properties to become an important candidate for new green adjuvants. DATEM, widely recognized as a powerful emulsifier in the food industry, also warrants examination for its potential applications in plant protection.
This article systematically compares the performance of PGE and DATEM in plant protection oil formulation systems from four dimensions: molecular structure, interfacial behavior, application effects, and environmental safety.
Basic Characteristics Comparison of PGE and DATEM
1.1 PGE: Polyglycerol Esters of Fatty Acids
PGE is a nonionic emulsifier produced by esterifying polyglycerol with fatty acids. Its core structural feature is the hydrophilic polyglycerol head group, consisting of multiple glycerol units linked by ether bonds, forming a "multi-branched" three-dimensional structure.
Structural Features:
Hydrophilic head: Polyglycerol with an average degree of polymerization of 1–3, providing multiple hydroxyl sites
Hydrophobic tail: Fatty acid chains with 8–16 carbons (e.g., caprylic acid, capric acid, lauric acid)
Molecular configuration: "Dendritic" or "star-shaped" distribution with significant steric hindrance
Core Advantages:
Excellent interfacial adsorption capacity, effectively reducing oil-water interfacial tension
As a nonionic emulsifier, insensitive to electrolytes and pH changes
Derived from renewable plant raw materials with good biodegradability
Can serve as a "built-in" drift retardant, effectively controlling droplet drift during spraying
1.2 DATEM: Diacetyl Tartaric Acid Esters of Mono- and Diglycerides
DATEM is renowned in the food industry as the "king of dough strengthening." Its molecular structure contains a unique diacetyl tartaric acid group, which imparts special hydrophilic-lipophilic balance characteristics.
Structural Features:
Hydrophilic head: Tartaric acid group with two acetyl groups, providing moderate hydrophilicity
Hydrophobic tail: Mono- and diglyceride fatty acid ester chains
Molecular configuration: "Wedge-shaped" with significant steric hindrance
Core Advantages:
Excellent oil solubility, completely miscible with oils and most oil-soluble solvents
Good stabilization effect on oil-water interfaces
Proven superior gluten-strengthening capacity in baking applications
3 Quick Feature Comparison
| Feature | PGE | DATEM |
|---|---|---|
| Chemical Type | Nonionic | Nonionic |
| Hydrophilic Head | Polyglycerol chain (2–3 glycerol units) | Diacetyl tartaric acid group |
| Hydrophobic Tail | C8–C16 fatty acids | Mono/diglyceride fatty acid esters |
| HLB Range | Broad, adjustable via degree of polymerization | Approximately 9–10 |
| Water Solubility | Varies with degree of polymerization | Low, dispersible in water |
| Oil Solubility | Good | Excellent (completely miscible) |
| Biodegradability | Good (renewable raw materials) | Degradable, but in different application domains |
| Primary Application | Pesticide adjuvants, food, cosmetics | Baked goods primarily |
Key Performance Metrics in Plant Protection Oil Formulations
In crop protection applications, evaluating emulsifier systems typically involves the following key metrics:
- Emulsion stability: Whether the emulsion remains uniformly dispersed without separation or precipitation
- Interfacial tension reduction: Lowering tension between the spray liquid and leaf surface for improved spreading and wetting
- Drift control: Reducing droplet drift during spraying to enhance target deposition efficiency
- Leaf penetration enhancement: Facilitating active ingredient penetration through the leaf cuticle
- Environmental safety: Biodegradability, crop safety profile
Performance of PGE in Plant Protection Oil Formulations
1 Proven Advantages
Emulsification and Interfacial Activity
As a nonionic surfactant, PGE effectively stabilizes oil-water interfaces. Research indicates that glycerol fatty acid esters (the parent structure of PGE) can simultaneously reduce both the surface tension of droplets and the interfacial tension between droplets and leaf surfaces, substantially improving pesticide wettability and spreadability.
Drift Control
Clariant's Synergen™ PGE product, with polyglycerol ester as its core ingredient, serves as a "built-in drift retardant" in aqueous formulations, significantly reducing droplet drift during spraying while improving spray retention and crop safety.
Green Sustainability
PGE is derived from plant oils (e.g., coconut oil), exhibits good biodegradability, requires no hazardous labeling, and is gentle on crops. This aligns perfectly with the current industry trend toward "reduced dosage with enhanced efficacy and green environmental protection."
Formulation Compatibility
PGE can be combined with methylated seed oil (MSO) and other components to form synergistic systems. For example, when PGE is blended with MSO, PGE stabilizes the emulsion while MSO swells the leaf surface structure and facilitates rapid penetration of active ingredients.
2 Limitations
Research on PGE in crop protection remains an evolving field. Known limitations include:
PGE products with different degrees of polymerization and esterification exhibit significantly different performance profiles, requiring precise selection during formulation design
Some high-polymerization PGE types may experience crystallization issues at low temperatures
Potential Analysis of DATEM Application in Plant Protection Oil Formulations
1 Transferable Advantages of DATEM
Although DATEM is currently used primarily in the food industry, its physicochemical properties suggest potential for cross-application to crop protection:
- Excellent Oil Solubility
- DATEM is completely miscible with oils and most oil-soluble solvents, enabling smooth integration into oil-based formulation systems.
- Interfacial Stabilization Capability
- In food systems, DATEM has been proven effective at stabilizing oil-water emulsions-a capability that could also be valuable in crop protection EW (emulsion in water) and SE (suspension emulsion) formulations.
- Inspiration from Gluten Network Building
- DATEM strengthens protein network structures in dough through hydrophobic interactions. By analogy, this "interfacial assembly" capability may contribute to forming more stable and longer-lasting active ingredient films on leaf surfaces.
2 Application Gaps for DATEM in Crop Protection
Currently, systematic research on DATEM in plant protection oil formulations remains insufficient. In existing literature, DATEM appears more frequently in food additive catalogs rather than pesticide adjuvant lists. This is attributable to several factors:
- Different application histories: DATEM's development and application have long focused on the food industry; cross-domain expansion requires further validation
- Different molecular design objectives: DATEM's molecular structure is oriented toward protein interactions rather than plant leaf surface interfacial behavior
- Regulatory barriers: Pesticide adjuvants require specialized toxicological and ecotoxicological data; DATEM's regulatory data in the crop protection domain are relatively lacking
Comprehensive Comparison of the Two Emulsifier Systems
| Comparison Dimension | PGE System | DATEM System |
|---|---|---|
| Interfacial Activity | ★★★★★ Well-validated | ★★★ Mature in food systems; needs validation in crop protection |
| Drift Control | ★★★★★ Commercially applied | ☆ No research reports available |
| Green Attributes | ★★★★★ Biodegradable, no hazard labeling | ★★★ Edible, but insufficient crop protection safety data |
| Formulation Maturity | ★★★★ Multiple commercial products available | ★★ Primarily at laboratory or conceptual stage |
| Cost-Effectiveness | ★★★★ Relatively mature | ★★ Requires further validation |
Key Conclusion:
In plant protection oil formulations, the PGE system currently holds a clear advantage. Its performance has been validated in actual commercial products, particularly excelling in drift control, emulsion stabilization, and green sustainability. While DATEM possesses theoretical cross-application potential, it lacks systematic empirical validation in crop protection scenarios and cannot directly replace PGE's position in agricultural adjuvants in the short term.
Frontier Trends: Emulsifier Innovation in Green Pesticide Formulations
PGE's success in pesticide adjuvants reflects a broader trend-pesticide formulations are transitioning from "high-toxicity, high-efficiency" toward "low-toxicity, high-efficiency, green, and sustainable."
In recent years, plant essential oils (EO) with antimicrobial activity have been registered and used as green botanical pesticides. However, traditional surfactant-stabilized essential oil emulsions suffer from rapid volatilization, low utilization rates, and the potential biotoxicity of surfactants. This has spurred the development of novel green emulsifiers:
- Janus nanosheet technology: A team at Shihezi University developed tannic acid-titanium/polystyrene Janus nanosheets that can replace traditional surfactants for efficient emulsification while reducing cytotoxicity by 29.17%
- Multifunctional PGE-derived systems: Introducing functional groups onto PGE backbones to achieve integrated "emulsification + efficacy enhancement + controlled release"
This trend indicates that the competition among emulsifiers for plant protection oil formulations will not merely be between PGE and DATEM, but will evolve toward multifunctional, green, and precision-oriented solutions.
Conclusion
One-Sentence Summary:
PGE has successfully crossed over from a food ingredient to a "powerhouse" in pesticide adjuvants, establishing a leading position in plant protection oil formulations through superior interfacial properties, drift control capabilities, and green attributes. DATEM, despite its structural highlights and cross-application potential, requires more empirical validation-the choice of emulsifier for plant protection ultimately depends on real-world field performance.
