Evaporation-induced assembly of colloidal clusters into superclusters with nonconvex deltahedral geometry

Abstract

Using small colloidal clusters with dumbbell, triplet, tetrahedral, octahedral geometry as elementary building blocks, we investigate the templated-assisted cluster-cluster aggregation into hierarchical clusters, namely superclusters, by means of Monte Carlo simulations. We find that the colloidal superclusters made of dumbbells and triplets produces a unique structural motif that is similar to that of clusters of single colloids, whereas the superclusters composed of tetrahedral and octahedral clusters possess a more complex structure. However, despite their complexity, such structures can be predicted based on a decomposition using triplets as a core and the number of initial “building block” clusters. In particular, a majority of the observable superclusters are members of a particular category of nonconvex deltahedra (Cundy deltahedra). These findings could be useful in preparation of complex colloidal molecules.