A change in stripes for cholesteric shells via anchoring in moderation

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.

27 pages, 10 figures

References in corpus (8)

• The Geometry of Soft Materials: A Primer
• Nematic textures in spherical shells
• Chiral nematic self-assembly of minimally surface damaged chitin nanofibrils and its load bearing functions
• Topological defects in cholesteric liquid crystal shells
• Waltzing route towards double-helix formation in cholesteric shells
• Lassoing saddle splay and the geometrical control of topological defects
• Instability patterns in ultrathin nematic films: comparison between theory and experiment
• The Geometry of the Cholesteric Phase

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• Cholesteric shells: two-dimensional blue fog and finite quasicrystals
• Undulation instabilities in cholesteric liquid crystals induced by anchoring transitions
• Contact Topology and the Structure and Dynamics of Cholesterics
• Ionically charged topological defects in nematic fluids
• Dissipative systems with nonlocal delayed feedback control
• Lattice Boltzmann modeling of cholesteric liquid crystal droplets under an oscillatory electric field
• Three-dimensional modeling of chiral nematic texture evolution under electric switching