Electric-field induced shape transition of nematic tactoids

TL;DR

This study demonstrates that electric fields can induce significant elongation and shape transition in nematic chitin tactoids, with the process being reversible and driven by elastic and hydrodynamic effects.

Contribution

It provides experimental and numerical evidence of electric-field-induced shape transitions in nematic tactoids, highlighting the dominant role of anchoring in elastic energy contributions.

Findings

Tactoids can stretch to aspect ratios over 15 under electric fields.

Shape transition from spindle-like to cigar-like is reversible.

Elongation involves hydrodynamic flow and is dominated by anchoring effects.

Abstract

The occurrence of new textures of liquid crystals is an important factor in tuning their optical and photonics properties. Here, we show, both experimentally and by numerical computation, that under an electric field chitin tactoids (i.e. nematic droplets) can stretch to aspect ratios of more than 15, leading to a transition from a spindle-like to a cigar-like shape. We argue that the large extensions occur because the elastic contribution to the free energy is dominated by the anchoring. We demonstrate that the elongation involves hydrodynamic flow and is reversible, the tactoids return to their original shapes upon removing the field.