# A change in stripes for cholesteric shells via anchoring in moderation

## TL;DR

This study explores how weak anchoring conditions influence cholesteric liquid crystal shells, revealing new surface structures and defect interconversions, with implications for biological systems and material design.

## Contribution

It introduces a detailed analysis of anchoring-induced state transitions and defect dynamics in cholesteric shells using experimental methods and Landau-de Gennes modeling.

## Key findings

- Identification of new shell surface states with striped patterns
- Demonstration of defect interconversion via anchoring modifications
- Simulation of cholesteric configurations as a function of anchoring strength

## Abstract

Chirality, ubiquitous in complex biological systems, can be controlled and quantified in synthetic materials such as cholesteric liquid crystal (CLC) systems. In this work, we study spherical shells of CLC under weak anchoring conditions. We induce anchoring transitions at the inner and outer boundaries using two independent methods: by changing the surfactant concentration or by raising the temperature close to the clearing point. The shell confinement leads to new states and associated surface structures: a state where large stripes on the shell can be filled with smaller, perpendicular sub-stripes, and a focal conic domain (FCD) state, where thin stripes wrap into at least two, topologically required, double spirals. Focusing on the latter state, we use a Landau-de Gennes model of the CLC to simulate its detailed configurations as a function of anchoring strength. By abruptly changing the topological constraints on the shell, we are able to study the interconversion between director defects and pitch defects, a phenomenon usually restricted by the complexity of the cholesteric phase. This work extends the knowledge of cholesteric patterns, structures that not only have potential for use as intricate, self-assembly blueprints but are pervasive in biological systems.