Real-time tracking of nanoparticle self-assembling using GISAXS

The self-assembling of iron oxide nanoparticles deposited on a substrate was studied employing the in situ time-resolved grazing incidence small-angle X-ray scattering with a temporal resolution of 28 ms. After the evaporation of the solvent, an ordered monolayer exhibiting a hexagonal close-packed arrangement of nanoparticles was found. The X-ray scattering data from the drop did not show a presence of ordered clusters in the drop volume and/or ordered islands at the drop surface. Three stages of the drop evaporation process were distinguished and analysed.