Finite-Size Colloidal Constructs Designed through Self-Assembly of Defective Colloidal Molecules*

Engineering various types of structures through self-assembly of colloidal particles is a powerful approach in material design and processing. While simple colloidal building blocks provide a number of well-known structures, more complex building blocks, such as colloidal molecules, are needed to create novel structures with desired functionalities and tunable properties.

In this study, we use computational techniques to identify, investigate, and exploit self-assembly paradigms that are made possible through the use of defective colloidal molecules. Specifically, we study how defective units, which are typically missing one or two particles compared to the regular units, can be taken advantage of to build finite-size constructs that would otherwise be inaccessible. We further demonstrate different types of finite-size, self-limiting, ‘supermolecules’ that can be assembled through engineered directional interactions between defective and regular colloidal molecules. We use Molecular Dynamics (MD) simulations to study the thermodynamics and kinetics of self-assembly, and investigate the phase behavior of the resulting colloidal constructs as a function of building block particle size ratio.