Synthesis of asymmetric dumbbell-like SiO2 nanoparticles in aqueous phase and their emulsification properties

Dumbbell-like SiO2 nanoparticles were synthesized by a simple chemical process in aqueous phase. Prior to the preparation, 3-aminopropyl triethoxysilane (KH550) and 3-chloropropyl triethoxysilane (KH230) were used as modifiers for the surface modification of SiO2 nanoparticles in SiO2 hydrosol. By mixing the SiO2 hydrosol modified by KH550 and KH230, respectively, the dumbbell-like SiO2 nanoparticles were obtained via the reaction between the -NH2 and -CH2Cl groups on the surface of the two SiO2 nanoparticles. The dumbbell-like SiO2 nanoparticles were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS). The results showed that the modified SiO2 nanoparticles are covalently coupled in a one-to-one manner. Detailed DLS analysis indicated that about 90% of the single nanoparticles were involved in the coupling reaction and formed new dumbbell-like SiO2 nanoparticles when the ratio of the two kinds of surface modified SiO2 was 1:1. Furthermore, the dumbbell-like SiO2 nanoparticles can be deployed as particle emulsifiers for stabilizing oil-water model systems during emulsification. [GRAPHICS] .

Automated summary

Dumbbell-like SiO2 nanoparticles were synthesized in aqueous phase using a simple chemical process. These nanoparticles were surface modified with 3-aminopropyl triethoxysilane and 3-chloropropyl triethoxysilane and covalently coupled to form dumbbell-like structures. The resulting nanoparticles can be used as emulsifiers to stabilize oil-water model systems.