Encapsulation of the flumethrin into the silica particle with the aid of surfactants having different HLB values

In this study, the required HLB (rHLB) value of flumethrin, type II pyrethroid insecticide, was determined and flumethrin was encapsulated into silica particle using TEOS as shell material with the help of different surfactants. Tween80 / Span80 and Tween20 / Span20 surfactant blends were used as surfactants to determine the HLB value of flumethrin. The rHLB value of the flumethrin was determined to be 15 with a series of emulsions prepared with surfactant blends with different HLB values. The HLB value used in the encapsulation stage of flumethrin was prepared using anionic and cationic surfactants except for the known non-ionic surfactants. Twenty-five blends of Twen20 / Span20 and Tween80 were used as non-ionic surfactants while SDS was used as anionic surfactant and CDMEB as cationic surfactant. The prepared emulsion was poured into the base solution with pH = 11,5 at one time and the capsulation process were completed. NaOH as a strong base and NH3 as a weak base were used. The particle size of the prepared emulsion and the capsules formed were measured by the DLS device. The amount of flumethrin encapsulated in the systems considered to be encapsulated and the release of flumethrin in the body fluid was determined by HPLC. In addition, the resulting capsules were visualized with TEM.