Microstructure and Surface Behavior of Oxide and Composite Nanoparticles Prepared by Flash Creation Method

Dispersion behavior of nanoparticles in organic solvent depends on surface molecular structure, even if the material and size of particles are same. In order to discuss the effect of surface conditions of nanoparticles on dispersion behavior in organic solvent and surface modification behavior, single phase SiO2 and TiO2 nanoparticles and SiO2-TiO2 composite particles were prepared by using flash creation method (FC method) with different thermal source, DC plasma or burner. By the observation of TiO2-SiO2 composite particles by TEM-EDS system, the microstructure of composite particles was estimated that SiO2 layer coated on core TiO2 nanoparticles. Surface OH group structure, dispersion behavior in N-methyl-2-pyrrolidone (NMP) of each TiO2 nanoparticles was depended on the thermal source of FC method. When thermal source used was burner, the high OH group density and well dispersion behavior was observed. However, after surface modification by silane coupling agent, the aggregate size of TiO2 nanoparticles prepared by DC plasma in NMP was decreased.