Two-dimensional, blue phase tactoids

TL;DR

This paper uses advanced simulations to explore the formation, dynamics, and shape reconfigurations of two-dimensional blue phases in cholesteric liquid crystal monolayers, revealing new stable structures and morphologies.

Contribution

It demonstrates the controllable formation and stability of 2D blue phases and diverse droplet shapes by constraining cholesteric liquid crystals with varying parameters.

Findings

Reproduction of 2D blue phases with hexagonal half-skyrmion lattices

Observation of reconfigurable droplet shapes including star-shaped morphologies

Identification of stable structures by tuning chirality, surface tension, and elastic constants

Abstract

We use full nematohydrodynamic simulations to study the statics and dynamics of monolayers of cholesteric liquid crystals. Using chirality and temperature as control parameters we show that we can recover the two-dimensional blue phases recently observed in chiral nematics, where hexagonal lattices of half-skyrmion topological excitations are interleaved by lattices of trefoil topological defects. Furthermore, we characterise the transient dynamics during the quench from isotropic to blue phase. We then proceed by confining cholesteric stripes and blue phases within finite-sized tactoids and show that it is possible to access a wealth of reconfigurable droplet shapes including disk-like, elongated, and star-shaped morphologies. Our results demonstrate a potential for constructing controllable, stable structures of liquid crystals by constraining 2D blue phases and varying the chirality, surface tension and elastic constants.