Positive charge pesticide nanoemulsions prepared by the phase inversion composition method with ionic liquids

Abstract

The deposition of pesticide liquid droplets on plant surfaces is of great importance in agricultural application. More than 50% of agrochemicals are lost and wasted during the spraying and wetting processes. Because the surfaces of plant leaves are negatively charged, we produced a kind of positive charge lambda-cyhalothrin loaded oil-in-water nanoemulsion in the system water/EL-80-Span 60/solvent 150# via the phase inversion composition (PIC) method with addition of Ionic Liquids (ILs). The electrostatic interaction between the negative charge surface and positive charge droplet would highly increase the wetting property. The results show that the positive zeta potential of nanoemulsion droplets gained along with the increase concentration of P₁₄₄₄₄Br, but with the increase concentration of P₄₄₄₄Br, the negative zeta potential of nanoemulsion droplets changed slightly and stayed around −17.8 mV (without any ILs). Besides, we explored the rheology characteristic of prepared nanoemulsions. Additionally, the contact angle experiments show that the positively charged nanoemulsions have a stronger adsorption on the negative surface and the contact angle decreased along with the increase of positive charge. Significantly, with addition of ILs, the nanoemulsions showed an excellent long-term stability due to electrostatic repulsion between droplets and homogeneous nanoscale droplet size. The highly stable pesticide nanoemulsions are of great importance in practical application and the nanoemulsions prepared with ILs offered a good potential as a carrier for drug delivery.