Single step synthesis of 5–30 nm monodisperse silica nanoparticles: Important experimental parameters and modeling

Controlling the size distribution of a suspension of nanoparticles is often critical for their usefulness. We explore the influence of mixing conditions (stirring speed and reactor volume) and temperature on the characteristics of silica nanoparticles obtained by a recently described two-phase reaction. Using small angle X-ray scattering, we show that the size distribution is mainly controlled by the evolution of the supersaturation during the nucleation stage and by the remaining reagents available for growth. We also demonstrate the possibility to increase the critical supersaturation using sharp temperature gradients. This is tentatively quantified in light of the classical nucleation theory.