Synthesis of nanometric silica particles via a modified Stober synthesis route

In this paper we describe a simple modification of the classic Stober reaction enabling a high temperature synthesis of nanometric silica particles with diameters less than 100 nm in sealed reaction tubes. This could be reached due to the replacement of the basic catalyst ammonia by ethanolamine. Thus, high temperature synthesis up to 80 degrees C can be run without facing the risk of bubble formation inside the reaction tube. The modified synthesis route enables the synthesis of spherical silica nanoparticles with mean diameters between 28 and 647 nm and standard deviations less than 10% as well as smooth surface structures. This work deals with basic studies on the use of ethanolamine for the synthesis of silica nanoparticles in alkaline media in sealed reaction tubes under ambient pressure. These include experiments on the adjustment of the particle size depending on the composition of the reaction solution and the temperature. In addition, reaction kinetics of the particle formation process are monitored as a function of temperature and the influence of the mixing time on the particle size is investigated.