Geometry-guided colloidal interactions and self-tiling of elastic dipoles formed by truncated pyramid particles in liquid crystals

TL;DR

This paper introduces truncated pyramidal colloidal particles in liquid crystals that form elastic dipoles, enabling novel self-assembly into various ordered structures with potential applications in photonics.

Contribution

Development of new colloidal particles with geometry-guided interactions that facilitate complex self-organization in liquid crystals.

Findings

Particles form nematic elastic dipoles with long-range interactions.

Demonstration of self-tiling into crystalline and quasicrystalline arrays.

Interactions explained via electrostatics analogy and symmetry considerations.

Abstract

The progress of realizing colloidal structures mimicking natural forms of organization in condensed matter is inherently limited by the availability of suitable colloidal building blocks. To enable new forms of crystalline and quasicrystalline self-organization of colloids, we develop truncated pyramidal particles that form nematic elastic dipoles with long-range electrostaticlike and geometry-guided low-symmetry short-range interactions. Using a combination of nonlinear optical imaging, laser tweezers, and video microscopy, we characterize colloidal pair interactions and demonstrate unusual forms of self-tiling of these particles into crystalline, quasicrystalline, and other arrays. Our findings are explained using an electrostatics analogy along with liquid crystal elasticity and symmetry breaking considerations, potentially expanding photonic and electro-optic applications of colloids.