Functionally modified monodisperse core-shell silica nanoparticles: Silane coupling agent as capping and size tuning agent

Vinyltriethoxysilane (VTEOS) has been used as capping and size tuning agent to prepare monodisperse core-shell silica hybrid spheres. When VTEOS was used, the relative standard deviation below 3% for silica hybrid spheres can be produced by changing the concentration of VTEOS and the ammonia catalyst. The obtained hybrid particles were characterized and confirmed by various technologies including Fourier transform infrared (FT-IR) spectroscopy, FT-Raman spectroscopy, ²⁹Si CP (cross-polarization) MAS NMR, thermal analysis, particle size distribution, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). FT-IR, FT-Raman, ²⁹Si CP MAS NMR spectra and thermal analysis confirm the existence of vinyl groups on hybrid particles. Particle size distribution, FE-SEM and TEM reveal the uniformity in size/shape and the core-shell structure of hybrid particles. The influence of experiment parameters on the resulting particles, the capping and size tuning actions of other silane coupling agents (SCAs) were investigated herein as well.