Preparation and Characterization of Oil-in-Water (O/W) Nanoemulsions

Abstract

Nanoemulsions (NEs) have small and uniform droplet size, in the range of 20 to 200 nm. Recently, oil-in-water based NEs have been used for pesticide formulation due to their high kinetic stability, optical transparency and low viscosity. The smaller droplet size of o/w NEs results into increase in surface area, which helps in efficient sprinkling of pesticide on crops to prevent the crops from any disease. Therefore, present work focuses on the development of transparent and stable o/w NEs. The neem oil based NEs have been synthesized using a high energy method (ultrasonication technique) and characterized in terms of their stability. Different combinations of oil, water and surfactant have been tested and the optimized combination was found at ratio a of 1:2 for neem oil and water. The average particle size and polydispersity index for sample obtained at optimized parameters were found in the range of 10-20 nm and 0.15, respectively. Rheological behavior of these samples was also studied at different temperatures, and the variation of viscosity with rate of shear and shear stress with shear rate were observed. Also, a brief literature survey was carried out to study the aggregation behavior of surfactant using molecular dynamics.