Nanoparticle production by solvent-free extrusion emulsification

This study examines the effect surfactants have on the mechanisms of solvent-free extrusion emulsification method featuring a twin-screw extruder. Two sets of surfactants were studied in this work, three anionic surfactants: SDBS, Unicid 350, Calfax, and three non-ionic surfactants: Igepal CO-890, Brij 58, Synperonic F-108. Comparing the anionic surfactants, it was found that both SDBS and Calfax exhibited great particle stabilization characteristics and resulted in 100-200 nm sized particle emulsions, while Unicid 350 was seen to result in coarse particle generation in the 100-200 µm size range. Comparing the non-ionic surfactants, it was found that Synperonic F-108 was the least successful of the three, and did not pass initial bench testing. Igepal CO-890 and Brij 58 both produced nano-sized emulsions, but with Brij 58 only a fraction of extrudate was true emulsified material, with the majority of the polymer exiting the process without emulsification. Overall it was found that a higher molar concentration of non-ionic surfactants was required to achieve results similar to those found with SDBS and Calfax.