Mesoscale structure of chiral nematic shells

• Published in: Soft matter Vol. 12; no. 44; pp. 8983 - 8989
• Main Authors: Zhou, Ye, Guo, Ashley, Zhang, Rui, Armas-Perez, Julio C, Martínez-González, José A, Rahimi, Mohammad, Sadati, Monirosadat, de Pablo, Juan J
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 09.11.2016
• Subjects: Chirality; Crystal defects; Droplets; Formalism; Heterogeneity; MATERIALS SCIENCE; Mesoscale phenomena; Nematic; Nematic crystals
• ISSN: 1744-683X; 1744-6848
• DOI: 10.1039/c6sm01284a

There is considerable interest in understanding and controlling topological defects in nematic liquid crystals (LCs). Confinement, in the form of droplets, has been particularly effective in that regard. Here, we employ a Landau-de Gennes formalism to explore the geometrical frustration of nematic order in shell geometries, and focus on chiral materials. By varying the chirality and thickness in uniform shells, we construct a phase diagram that includes tetravalent structures, bipolar structures (BS), bent structures and radial spherical structures (RSS). It is found that, in uniform shells, the BS-to-RSS structural transition, in response to both chirality and shell geometry, is accompanied by an abrupt change of defect positions, implying a potential use for chiral nematic shells as sensors. Moreover, we investigate thickness heterogeneity in shells and demonstrate that non-chiral and chiral nematic shells exhibit distinct equilibrium positions of their inner core that are governed by shell chirality c . In this work, we study the phase behavior of micron ChLC shells by varying the chirality, shell thickness and the degree of asymmetry, based on a Landau-de Gennes theory.