Evidence of Size Stratification in Colloidal Glass Microgranules Realized by Rapid Evaporative Assembly

Evaporation is a ubiquitous phenomenon. Rapid evaporation of the continuous phase from micrometric colloidal droplets can be used to realize nanostructured microgranules, constituting the assembled nanoparticles. One of the important aspects of such nonequilibrium assembly is the nature of the packing of nanoparticles in the microgranules. The present work demonstrates the evidence of size stratification of the nanoparticles in such far-from-equilibrium configurations. Small-angle X-ray scattering, in combination with particle packing simulation, reveals the large on top-type stratification in such assembled microgranules, where the larger particles get concentrated at the outer shell of the granules while the smaller particles reside in the core region. It also reveals the presence of local clusters in such a rapid evaporative assembly in aerosolized colloidal droplets.

Automated summary

This study demonstrates the evidence of size stratification of nanoparticles in far-from-equilibrium configurations by using small-angle X-ray scattering and particle packing simulation, revealing the concentration of larger particles at the outer shell and the residence of smaller particles in the core region in assembled microgranules.