Flow field induced crystallization of multicomponent colloids.

Abstract

Field-directed assembly presents a powerful approach for directing the organization of colloidal particles into long-range crystalline orderings. While their ability to tune colloidal crystallization has been widely studied, insights into how they mediate the formation of such structures remain an open question. Here, we utilize an optically generated axisymmetric flow field as an external stimulus to direct the cocrystallization of a ternary system of colloidal particles. We show that the presence of flow fields fluidizes kinetically trapped clusters, suppressing fractionalization tendencies and promoting the formation of cocrystalline assemblies. By developing a model to simulate flow-mediated processes in coarse-grained simulation, we additionally leverage computational screening to identify experimental systems capable of forming complex morphologies previously unobserved in spherical colloidal assemblies, all of which are then validated in experiments. Our integrated experiment-simulation study showcases how axisymmetric flow can serve as a powerful handle to direct the cocrystallization in a multicomponent colloidal system. Furthermore, it provides a path for merging equilibrium and nonequilibrium processes for use in self-assembly, opening new avenues for predictive design of complex materials at the nanoscale.