Inverse design of compression-induced solid – solid transitions in colloids

Abstract

Ongoing developments in colloidal particle synthesis show promise for using colloids as building blocks for reconfigurable, functional materials, but their rational design remains a challenge. Recent efforts to inversely design a colloidal particle from a self-assembled target structure at a single state point have proven successful even for complex colloidal crystals, replacing trial-and-error searches. Can such approaches be used to design a particle capable of assembling into multiple target structures under multiple conditions, thereby designing a reconfigurable colloidal crystal? Here we present a computational approach for the design of colloids that exhibit distinct target behaviours under different thermodynamic conditions. By extending the digital alchemy inverse design framework to multiple state points, we design hard particle shapes that entropically self-assemble two different colloidal crystal structures at two different densities; upon a small density change, the system reliably reconfigures between the two solids. We also find that the optimal shape satisfying two constraints is not simply an average of the two optimal shapes from each state point, and therefore is not easily intuited.