Correlation between synthesis parameters and properties of magnetite clusters prepared by solvothermal polyol method

The solvothermal polyol reaction is one of the most common methods known in the literature to synthesize magnetite nanoparticles and especially clusters. Despite this, its reaction mechanism is still not definitely determined. In the course of this work, a polyol reaction with sodium acrylate as stabilizer was used as a representative example. By using analytic tools such as TEM/SEM, XRPD, FTIR and Raman spectroscopy, XPS and magnetization measurements, the influence of several reaction parameters was examined, some of them for the first time for this type of reaction. The results detailed here have consequences for reproducibility as well as scale-up for this reaction. Using NMR techniques, the surface coating of the clusters was also analyzed. It was found that the coating consists of a variety of molecules, not just the stabilizer added in the reaction. By varying the temperature, it was possible to produce maghemite clusters instead of magnetite ones. Finally, on the basis of detailed analysis of intermediates, a possible reaction mechanism was formulated and used to explain several of the earlier findings.