Evidence for spinodal phase separation in two-dimensional nanocrystal self-assembly

The drying of thin nanocrystal solution films creates a varied range of str uctured aggregate spatial patterns as a function of surface coverage. These images can be understood as predicted kinetic stages in the fluid-fluid sp inodal phase separation of a 2D van der Waals particle system. It is sugges ted that phase separation occurs due to increased van der Waals nanocrystal -nanocrystal interaction in the presence of air, as compared with the shiel ded interaction in organic solvents.