Ferroelectric nematic liquid crystal thermo-motor

TL;DR

This paper demonstrates a novel thermal gradient-induced circular motion in ferroelectric nematic liquid crystal drops, driven by the material's unique polarization and pyroelectric properties, revealing new fluid dynamics phenomena.

Contribution

It introduces a simple model explaining how ferroelectric polarization and thermal gradients induce laminar flow and particle rotation in ferroelectric nematic liquid crystals.

Findings

Thermal gradients cause circular particle motion in ferroelectric nematic drops.

Flow remains laminar despite particle motion, unlike turbulent natural phenomena.

Charged tracer particles reveal the flow dynamics driven by ferroelectric properties.

Abstract

A thermal gradient-induced circular motion of particles placed on ferroelectric nematic liquid crystal sessile drops is demonstrated and explained. Unlike hurricanes and tornadoes that are the prime examples for thermal motors and where turbulent flows are apparent, here the texture without tracer particles appears completely steady indicating laminar flow. We provide a simple model showing that the tangential arrangement of the ferroelectric polarization combined with the vertical thermal gradient and the pyroelectricity of the fluid drives the rotation of the tracer particles that become electrically charged in the fluid. These observations provide a fascinating example of the unique nature of fluid ferroelectric liquid crystals.