Colloidal interactions and unusual crystallization versus de-mixing of elastic multipoles formed by gold mesoflowers

TL;DR

This paper explores how gold mesoflowers induce elastic multipoles in nematic liquid crystals, leading to unique many-body interactions and novel colloidal crystal structures, advancing the design of colloidal self-assembly.

Contribution

It demonstrates the formation of elastic multipoles of various orders by gold mesoflowers and reveals unexpected many-body interactions and complex crystal structures.

Findings

Gold mesoflowers induce elastic monopoles and high-order multipoles.

Unexpected de-mixing behavior of elastic monopoles observed.

Formation of unusual colloidal crystals like hexadecapoles.

Abstract

Colloidal interactions in nematic liquid crystals can be described as interactions between elastic multipoles that depend on particle shape, topology, chirality, boundary conditions and induced topological defects. Here, we describe a nematic colloidal system consisting of mesostructures of gold capable of inducing elastic multipoles of different order. Elastic monopoles are formed by relatively large asymmetric mesoflower particles, for which gravity and elastic torque balancing yields monopole-type interactions. High-order multipoles are instead formed by smaller mesoflowers with a myriad of shapes corresponding to multipoles of different orders, consistent with our computer simulations based on free energy minimization. We reveal unexpected many-body interactions in this colloidal system, ranging from de-mixing of elastic monopoles to a zoo of unusual colloidal crystals formed by high-order multipoles like hexadecapoles. Our findings show that gold mesoflowers may serve as a designer toolkit for engineering colloidal interaction and self-assembly, potentially exceeding that in atomic and molecular systems.