DMREF/Collaborative Research: Synthesis of Colloidal Crystals Guided by Particle-Based Theory and Simulation

This Designing Materials to Revolutionize and Engineer our Future (DMREF) collaborative research project will use a combination of theory, numerical simulation, and experiment to discover and synthesize new crystalline materials that can enable the manufacturing of metamaterials. Metamaterials have unique periodic structures that can be used to manipulate electromagnetic or mechanical energy. The materials will be formed from the self-assembly of colloidal particles in suspension. This route to metamaterials is especially flexible, because many kinds of interactions among the particles can be exploited to form new crystalline materials. In addition, it allows better control over the formation process, which can reduce defects in the resulting crystalline structures. The results of the project will provide scientists and engineers with improved tools for identifying colloidal systems of interest, predicting stable crystalline structures, and guiding synthesis of the new materials.

Theory, simulation, and experiments will be integrated into a program to design systems of colloidal particles that assembly into desired crystalline structures. New theoretical and simulation methods will be developed to predict stable and metastable crystal structures in colloidal systems, with a focus on enhancing capabilities of classical density functional theory and applying hyper-parallel tempering simulation methods. Experimental tools for measuring and designing colloidal potentials and analyzing crystal structures will be extended to binary mixtures. The focus will be on developing and measuring suitable potentials for binary systems through the use of different particle sizes and materials, doublets/dumbbells, and Janus configurations, and on characterizing crystal structures using advanced confocal microscopy techniques. The results will be used to design colloidal systems that assemble into desired crystalline structures. Three specific platforms to be considered are solid-fluid and solid-solid polymorphic transitions in binary mixtures of spherical particles of different size and interaction potential, plastic to close-packed solid transitions for doublet/dumbbell particles, and the formation of non-close-packed structures for particles with orientation-dependent attraction (Janus).