Heuristic rule for binary superlattice coassembly: Mixed plastic mesophases of hard polyhedral nanoparticles

TL;DR

This paper introduces a simple heuristic rule for designing mixed nanoparticle systems that promotes the formation of stable, ordered superlattices by matching the transition pressures of individual components, enabling the creation of plastic-solid solutions.

Contribution

The paper proposes a new size-matching rule based on transition pressure alignment to facilitate the coassembly of mixed polyhedral nanoparticles into ordered structures.

Findings

Monte Carlo simulations confirm formation of plastic-solid solutions across compositions.

The rule applies to polyhedra from the truncated-cube family.

Ordered superlattices are achieved despite geometric incompatibilities.

Abstract

Sought-after ordered structures of mixtures of hard anisotropic nanoparticles can often be thermodynamically unfavorable due to the components' geometric incompatibility to densely pack into regular lattices. A simple compatibilization rule is identified wherein the particle sizes are chosen such that the order-disorder transition pressures of the pure components match (and the entropies of the ordered phases are similar). Using this rule with representative polyhedra from the truncated-cube family that form pure-component plastic-crystals, Monte Carlo simulations show the formation of plastic-solid solutions for all compositions and for a wide range of volume fractions.