Multifarious colloidal structures: new insight into ternary and quadripartite ordered assemblies

Abstract

DNA-mediated assembly of colloidal particles can be utilized to produce a variety of structures which may have desirable phononic, photonic, or electronic transport properties. Recent developments in linker-mediated assembly processes allow for interactions to be coordinated between many different types of colloidal particles more easily and with fewer unique sequences than direct hybridization. However, the dynamics of colloidal self-assembly becomes increasingly more complex when coordinating interactions between three or more distinct interacting elements. In such cases particle pairs with similar binding energies are allowed to interact unpredictably, and enthalpically degenerate binding sites will be noticeably more present while numerous secondary phases may also result from the self-assembly process. Therefore, it is necessary to develop procedures for predicting feasible superstructure geometries for these systems before they can be implemented in material design. Here we investigate the formation of multifarious ordered structures through self-assembly of multiple types of spherically symmetrical colloidal particles with a variety of interaction matrices. We utilize Molecular Dynamics (MD) simulations to study the growth behavior of systems with different types of interacting elements and different particle sizes, and also predict the formation and stability of the target structures. We also study the phononic spectra of various ternary structures in order to identify the influence of key structural parameters on phonon bandgap frequencies and ranges. Our results provide direct guidelines for designing ternary and quadripartite multifarious colloidal structures, and motivate new directions for future experimental work to target formation of multi-component colloidal superstructures beyond the well-established binary symmetries studied in the past.