# Dynamic tuning of the director field in liquid crystal shells using block copolymers

@article{Noh2020DynamicTO,
title={Dynamic tuning of the director field in liquid crystal shells using block copolymers},
author={JungHyun Noh and Yiwei Wang and Hsin-Ling Liang and Venkata Subba Rao Jampani and Apala Majumdar and Jan P. F. Lagerwall},
journal={arXiv: Soft Condensed Matter},
year={2020}
}
When a nematic liquid crystal (LC) is confined on a self-closing spherical shell, topological constraints arise with intriguing consequences that depend critically on how the LC is aligned in the shell. We demonstrate reversible dynamic tuning of the alignment, and thereby the topology, of nematic LC shells stabilized by the nonionic amphiphilic block copolymer Pluronic F127. Deep in the nematic phase, the director is tangential to the interface, but upon approaching the temperature TNI of the…
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## References

SHOWING 1-10 OF 157 REFERENCES
Tuning the defect configurations in nematic and smectic liquid crystalline shells
• Materials Science, Medicine
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
• 2013
It is demonstrated that inclusions in a shell can seed defects that cannot form in a pristine shell, adding a further means of tuning the defect configuration, and that shells in which the internal aqueous phase is not density matched with the LC will gently rearrange the internal structure upon a rotation that changes the influence of gravity.
Realignment of Liquid Crystal Shells Driven by Temperature-Dependent Surfactant Solubility
• Medicine, Materials Science
Langmuir : the ACS journal of surfaces and colloids
• 2019
It is suggested that LC shells can detect solutes in the continuous phase, provided there is sufficient probability that the solute migrates through the LC into the inner aqueous phase.
Towards tunable defect arrangements in smectic liquid crystal shells utilizing the nematic–smectic transition in hybrid-aligned geometries
• Materials Science
• 2012
We produce and investigate liquid crystal shells with hybrid alignment—planar at one boundary, homeotropic at the other—undergoing a transition between the nematic (N) and smectic-A (SmA) phases. The
Nematic-smectic transition under confinement in liquid crystalline colloidal shells.
• Materials Science, Medicine
Physical review letters
• 2011
We carry out the first study of smectic liquid crystalline colloidal shells and investigate how their complex internal structure depends on the director configuration in the nematic phase, preceding
Dielectrophoretic manipulation of the mixture of isotropic and nematic liquid
• Materials Science, Medicine
Nature communications
• 2015
It is shown that a nematic–isotropic mixture, a unique bi-liquid system, has potential for the fabrication of microstructures having an ordered phase within a disordered phase, or vice versa.
Influence of interface stabilisers and surrounding aqueous phases on nematic liquid crystal shells.
• Chemistry, Medicine
Soft matter
• 2016
In hybrid-aligned shells, with planar outer and homeotropic inner boundary (or vice versa), the N-I transition splits into two steps, with a consequent three-step textural transformation, as a result of the order-enhancing effect of a monolayer of radially aligned SDS molecules adsorbed at the homeotropic interface.
Sub-second dynamic phototuning of alignment in azodendrimer-doped nematic liquid crystal shells
• Materials Science
Journal of Molecular Liquids
• 2018
Abstract The alignment of nematic liquid crystal 5CB in micron-thick shells, suspended in and containing aqueous liquid phases, can be rapidly switched between radial (homeotropic) and tangential
Topological transformations in bipolar shells of nematic liquid crystals.
• Materials Science, Medicine
Physical review. E, Statistical, nonlinear, and soft matter physics
• 2009
In the case of nematic shells the two defects on the inner surface play a relevant role in the overall evolution process, and both involve the generation of a disclination ring that shrinks with time, eventually disappearing.
Extrinsic curvature effects on nematic shells.
• Physics, Medicine
Physical review letters
• 2012
The nematic elastic energy promotes the alignment of the flux lines of the nematic director towards geodesics and/or lines of curvature of the surface, which enables the manipulation of nematic alignment for the design of new materials and technological devices.
Spherical nematic shells with a prolate ellipsoidal core.
Experimental studies show that, when trapped inside a radial LC droplet, spherical particles with both homeotropic and planar anchoring are highly localized at the droplet's center, leading to the formation of peculiar hybrid and twisted structures.