Microfluidic Flow of Cholesteric Liquid Crystals

TL;DR

This study investigates how cholesteric liquid crystals behave under flow in microfluidic channels, revealing new dynamic regimes and flow responses relevant for applications and fundamental understanding.

Contribution

It provides the first detailed analysis of flow-induced morphological changes in cholesteric phases with complex director fields under various anchoring conditions.

Findings

Identification of multiple dynamic flow regimes

Flow response insights for cholesteric phases with complex patterns

Relevance for microfluidic applications involving cholesteric liquid crystals

Abstract

We explore the rheology and flow-induced morphological changes of cholesteric liquid crystal patterns subject to Poiseuille flow within a slab geometry, and under different anchoring conditions at the wall. Our focus is particularly on the behaviour of Cholesteric Fingers of the first kind and of Blue Phase II. Depending on the applied pressure gradient, we observe a number of dynamic regimes with different rheological properties. Our results provide the first insight into the flow response of cholesteric phases with fully two- or three-dimensional director field patterns and normal and planar degenerate anchoring conditions as commonly realised in experiments. They are also of high relevance for a fundamental understanding of complex liquid crystals in confinement and an important step towards future microfluidic applications that are based on cholesteric liquid crystals.