SAXS exploration of the synthesis of ultra monodisperse silica nanoparticles and quantitative nucleation growth modeling.

The production of highly monodisperse nanoparticles of precisely controlled size is a very important research field. It has important applications notably for the optical properties of nanoparticles (e.g. quantum dot) or nanoparticle assemblies (e.g. photonic band gap crystals) and for electromagnetic properties (e.g. information storage). Understanding monodisperse nanoparticle synthesis mechanism is based mostly on the Classical Nucleation Theory (CNT). It has been shown in the literature and in this work that CNT is able to predict the nanoparticle concentration and average size correctly. However, until recently only a few models based on CNT were able to predict the size distribution of the synthesized objects. In this work, we show that a CNT based model is not able to predict the size distribution of silica nanoparticles formed in a pure La Mer like nucleation growth process. Reasons for this discrepancy are discussed and should be taken into account to develop more complete models able to predict the size distribution especially if it is desired to use them as tools to optimize monodispersity.