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

Hai Pham-Van,Bich Do-Danh,Hoang Luc-Huy,Cuong Tran-Manh,Thuy Nguyen-Minh

doi:10.1063/1.5055638

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.

Highlights

Colloidal clusters or “colloidal molecules” are of great of interest for unique photonic, optical, magnetic and electric applications in addition to resembling pretty much those of molecules.1–5 Manoharan, Elsesser, and Pine6 reported a templated-assisted strategy for preparing large quantities of clusters consisting of colloidal spheres
After 7.5 × 106 and 107 Monte Carlo (MC) sweeps, these superclusters still exist in the stable state against thermal fluctuations (see Fig. 4(e)-(f))
A simple model for a binary mixture of emulsion droplets and colloidal spheres was previously used to explore the particular structures of small-size clusters, such as the dumbbell, triplet, tetrahedron, octahedron

Summary

INTRODUCTION

Colloidal clusters or “colloidal molecules” are of great of interest for unique photonic, optical, magnetic and electric applications in addition to resembling pretty much those of molecules. Manoharan, Elsesser, and Pine reported a templated-assisted strategy for preparing large quantities of clusters consisting of colloidal spheres. For a given number of constituent spheres, nc, the final clusters exhibit unique configurations Such optimal structures were later confirmed in computer simulations based on a pure geometrical confinement.. By considering various systems composed of one cluster species or of two different cluster species, together with emulsion droplets, we are able to predict the intricate superclusters structures formed. Such structures are very similar to nonconvex deltahedral structures which have not been observed both experimentally and numerically in colloidal molecules.

MODEL AND METHOD

Supercluster formation

Supercluster structure

CONCLUSIONS