Acousto-microfluidic Control of Liquid Crystals

TL;DR

This paper explores how microfluidic flows and acoustic fields influence the molecular orientation and optical properties of nematic liquid crystals, revealing new structures and potential for innovative sound-flow-confinement systems.

Contribution

It introduces a novel investigation of acoustic and flow effects on liquid crystals, identifying previously unknown structures and providing a theoretical framework for their interpretation.

Findings

Identification of new liquid crystal structures under combined flow and acoustic fields

Development of a state diagram based on flow and acoustic strength

Use of continuum theory simulations to interpret experimental results

Abstract

The optical properties of liquid crystals serve as the basis for display, diagnostic, and sensing technologies. Such properties are generally controlled by relying on electric fields. In this work, we investigate the effects of microfluidic flows and acoustic fields on the molecular orientation and the corresponding optical response of nematic liquid crystals. Several previously unknown structures are identified, which are rationalized in terms of a state diagram as a function of the strengths of the flow and the acoustic field. The new structures are interpreted by relying on calculations with a free energy functional expressed in terms of the tensorial order parameter, using continuum theory simulations in the Landau-de Gennes framework. Taken together, the findings presented here offer promise for the development of new systems based on combinations of sound, flow, and confinement.