Importance of leaf surface and formulation properties in predicting wetting outcomes

Area of Science:

• Agricultural Science
• Surface Chemistry
• Formulation Science

Background:

• Leaf wettability significantly impacts agrichemical spray retention, necessitating improved formulation strategies.
• Understanding leaf surface properties and formulation characteristics is crucial for effective pest management.

Purpose of the Study:

• To investigate the key surface and formulation properties governing leaf wetting by agrichemical sprays.
• To develop a predictive model for wetting outcomes across various leaf and synthetic surfaces.

Main Methods:

• Compiled an extensive database of 11 synthetic and 54 diverse leaf surfaces with 35 different formulations.
• Quantified surface properties (physical roughness, chemical polarity) and formulation properties (surface tension, polarity) using the wetting tension dielectric method and dielectric constant measurements.

Main Results:

• Physical roughness and chemical polarity of surfaces, along with formulation surface tension and polarity, were identified as primary wetting determinants.
• A comprehensive wetting model accurately predicted wetting outcomes (R² = 0.86) across all tested surfaces.
• The model demonstrated predictive capability for adjuvant formulations even without precise formulation polarity data.

Conclusions:

• Wetting phenomena can be effectively modeled across a broad spectrum of surfaces and solutions.
• The developed model offers potential for enhanced prediction of adjuvant formulation wetting, pending a method for quantifying formulation dielectric constant.
• This research advances the understanding of wetting drivers, facilitating the rational design and selection of adjuvants for specific applications.