Comparative study of the synthesis of silica nanoparticles in micromixer–microreactor and batch reactor systems

Two different reactors, namely a microreactor with an interdigital micromixer and a batch reactor, have been used to prepare silica nanoparticles. The effect of synthesis variables was studied, and the results are compared in terms of particle-size distribution and synthesis reproducibility for different reaction conditions. The microreactors operated with shorter nucleation times and a greater homogeneity in terms of temperature and composition. This resulted in narrower particle-size distributions and a lower polydispersity. The synthesis reproducibility and the reactant (TEOS) conversion were also higher when using micromixers compared with batch reactors for the same synthesis times. Because of these characteristics micromixer–microreactor systems appear as a promising alternative for the continuous synthesis of nanoparticles.

► Microreactors produce monodisperse nanoparticles with lower polydispersity than batch reactors.
► Synthesis reproducibility and reactant conversion are also higher when using micromixers.
► The microreactor shows a better mixing and a higher surface/volume ratio.