Influence of the surface limiting elasticity modulus on the impact behavior of droplets of difenoconazole-loaded mesoporous silica nanoparticles with associated SDS

Efficient pesticide formulation and regulation mechanism for improving the deposition of droplets on the leaves of rice (Oryza sativa L.)

BACKGROUND

The effective deposition of pesticide droplets on the target leaf surface is critical for improving the utilization of pesticides. We proposed a new way to enhance the droplet deposition on the target leaf surface by changing the properties of pesticide formulation, and this formulation can be sprayed directly or at a low dilution. In addition, it is a simple method to select a suitable concentration and formulation by evaluating the interfacial dilational rheological properties of pesticide droplets.

RESULTS

The wetting behavior of two types of pesticide formulations prepared by oil-based solvent on the rice leaf surface was investigated based on the surface free energy, surface tension, contact angle, adhesion tension, and adhesion work. The interfacial dilational rheological properties of different pesticide solutions were measured as a function of concentration. This study clearly demonstrates the fact that water-in-oil emulsion has a better wettability than oil-in-water emulsion, especially with the increase of the concentration of the solution, the droplets can be wetted and spread faster on the leaves. Compared with vegetable oil (methyl oleate), mineral oil (solvent oil No. 200) has smaller dilational modulus and surface tension, showing excellent wetting properties.

CONCLUSION

The water-in-oil emulsion prepared with solvent oil No. 200 has the smallest dilational modulus, and the spray droplets spread rapidly to the maximum wetting area on the rice leaves, which can be used in an ultra-low volume spray. The results provide new insights into how to increase the deposition of droplets on superhydrophobic leaf surfaces by screening formulations and concentrations. © 2021 Society of Chemical Industry.

A simple and effective strategy to enhance the stability and solid-liquid interfacial interaction of an emulsion by the interfacial dilational rheological properties

The development of an emulsion is an important challenge in many fields, such as agrochemicals, pharmaceutics, paints, cosmetics, inkjet printing, and food science. However, the traditional strategies that refer to the empirical value and complex secondary additives cannot reflect the influence of the structure, content, compound, and adsorption of emulsifiers. Here, we propose a simple and effective strategy to develop the emulsion, wherein the emulsifiers are chosen based on the dilational rheological properties of the interfacial films at the molecular level. The dilational rheological properties of polyoxyethylene (80) castor oil (EL-80), sorbitan monostearate (Span 60), and their emulsions were explored by the oscillating drop method. Based on the dilational rheological properties, the emulsions were prepared by the phase inversion emulsification technique. The results showed that the emulsion was stable and realized effective solid-liquid interfacial interaction, which was attributed to the large dilational modulus (intermolecular interaction) at the oil/water interface and loss modulus (molecular diffusion exchange) at the air/water interface. These factors reduced the Ostwald ripening and coalescence, and finally increased the spreading diameter. Additionally, the prochloraz 25% emulsion in water (EW) and difenoconazole 20% EW were developed to verify the feasibility of the strategy. Therefore, this research advances the understanding of an emulsion by interfacial dilational rheological properties, which can provide a simple and effective strategy to develop a stable emulsion and achieve an effective solid-liquid interfacial interaction of the emulsion.