Topological transformations of a nematic drop

TL;DR

This paper demonstrates a topological shape transformation in nematic liquid crystal droplets, changing from a sphere-like tactoid to a torus, driven by elastic anisotropy affecting molecular orientations.

Contribution

It reveals how elastic anisotropy causes topological shape changes in nematic droplets, providing insights into morphogenesis and shape control in soft materials.

Findings

Nematic droplets can transform from tactoids to tori.

Elastic anisotropy influences molecular splay and bend.

Shape transformation is driven by elastic constants.

Abstract

Morphogenesis of living systems involves topological shape transformations which are highly unusual in the inanimate world. Here we demonstrate that a droplet of a nematic liquid crystal changes its equilibrium shape from a simply-connected tactoid, which is topologically equivalent to a sphere, to a torus, which is not simply-connected. The topological shape transformation is caused by the interplay of nematic elastic constants, which facilitates splay and bend of molecular orientations in tactoids but hinders splay in the toroids. The elastic anisotropy mechanism might be helpful in understanding topology transformations in morphogenesis and paves the way to control and transform shapes of droplets of liquid crystals and related soft materials.