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

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
JungHyun Noh ◽  
Yiwei Wang ◽  
Hsin-Ling Liang ◽  
Venkata Subba Rao Jampani ◽  
Apala Majumdar ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Block Copolymers ◽  
Director Field ◽  
Dynamic Tuning

scholarly journals Photo-tunable epsilon-near-zero behavior in a self-assembled liquid crystal – nanoparticle hybrid material

2021 ◽  
Author(s):  
Amit Bhardwaj ◽  
Vimala Sridurai ◽  
Sachin A. Bhat ◽  
Channabasaveshwar V. Yelamaggad ◽  
Geetha G. Nair
Keyword(s):  
Liquid Crystal ◽  
Hybrid Material ◽  
Room Temperature ◽  
Dynamic Tuning ◽  
Actinic Light ◽  
Self Assembled ◽  
Epsilon Near Zero

A room temperature stable self-assembled liquid crystal metamaterial exhibits dynamic tuning of the epsilon-near-zero (ENZ) bandwidth on illumination with actinic light in the optical regime.

A Chiral Director Field in the Nematic Liquid Crystal Phase Induced by a Poly(.gamma.-benzyl glutamate) Chemical Reaction Alignment Film

Langmuir ◽  
1995 ◽  
Vol 11 (12) ◽  
pp. 4838-4843 ◽  
Author(s):  
Shigeru Machida ◽  
Taeko I. Urano ◽  
Kenji Sano ◽  
Yasushi Kawata ◽  
Kazuyuki Sunohara ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Chemical Reaction ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Director Field

Simulation and Experimental Measurement of Liquid Crystal Polymer Orientation During Injection Molding

MRS Advances ◽  
2018 ◽  
Vol 3 (39) ◽  
pp. 2311-2316
Author(s):  
Anthony Sullivan ◽  
Anil Saigal ◽  
Michael A. Zimmerman
Keyword(s):  
Liquid Crystal ◽  
Melt Processing ◽  
Engineering Properties ◽  
Liquid Crystal Polymers ◽  
Director Field ◽  
X Ray Scattering ◽  
Molecular Ordering ◽  
Orientation State ◽  
Degree Of Order ◽  
Good Agreement

AbstractLiquid crystal polymers (LCP’s) comprise a class of materials that derive desirable, but anisotropic, engineering properties from long-range molecular ordering. The ability to model the polymer texture is essential to the design of manufacturing processes for isotropic material production. Previous efforts to model LCP directionality have been primarily restricted to structured grids and simple geometries that demonstrate the underlying theory, but fall short of simulating realistic manufacturing geometries. In this investigation, a practical methodology is proposed to simulate the director field in full-scale melt-processing domains and wide-angle x-ray scattering (WAXS) is used to experimentally validate modeling results. It is shown that the model generates good agreement with experimental measurements of both the orientation state and degree of order.

On the Dynamics of the Weak Fréedericksz Transition for Nematic Liquid Crystals

2016 ◽  
Vol 20 (5) ◽  
pp. 1359-1380 ◽  
Author(s):  
Peder Aursand ◽  
Gaetano Napoli ◽  
Johanna Ridder
Keyword(s):  
Liquid Crystal ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Electric Field ◽  
Excited States ◽  
Difference Method ◽  
Static Case ◽  
Director Field ◽  
Implicit Finite Difference ◽  
Anchoring Strength

AbstractWe propose an implicit finite-difference method to study the time evolution of the director field of a nematic liquid crystal under the influence of an electric field with weak anchoring at the boundary. The scheme allows us to study the dynamics of transitions between different director equilibrium states under varying electric field and anchoring strength. In particular, we are able to simulate the transition to excited states of odd parity, which have previously been observed in experiments, but so far only analyzed in the static case.

scholarly journals Stable and Metastable Patterns in Chromonic Nematic Liquid Crystal Droplets Forced with Static and Dynamic Magnetic Fields

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 138 ◽  
Author(s):  
Jordi Ignés-Mullol ◽  
Marc Mora ◽  
Berta Martínez-Prat ◽  
Ignasi Vélez-Cerón ◽  
R. Santiago Herrera ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Boundary Conditions ◽  
Isotropic Phase ◽  
Director Field ◽  
Line Defects ◽  
The One ◽  
Bulk Structures ◽  
Microscopy Images

Spherical confinement of nematic liquid crystals leads to the formation of equilibrium director field configurations that include point and line defects. Driving these materials with flows or dynamic fields often results in the formation of alternative metastable states. In this article, we study the effect of magnetic field alignment, both under static and dynamic conditions, of nematic gems (nematic droplets in coexistence with the isotropic phase) and emulsified nematic droplets of a lyotropic chromonic liquid crystal. We use a custom polarizing optical microscopy assembly that incorporates a permanent magnet whose strength and orientation can be dynamically changed. By comparing simulated optical patterns with microscopy images, we measure an equilibrium twisted bipolar pattern within nematic gems that is only marginally different from the one reported for emulsified droplets. Both systems evolve to concentric configurations upon application of a static magnetic field, but behave very differently when the field is rotated. While the concentric texture within the emulsified droplets is preserved and only displays asynchronous oscillations for high rotating speeds, the nematic gems transform into a metastable untwisted bipolar configuration that is memorized by the system when the field is removed. Our results demonstrate the importance of boundary conditions in determining the dynamic behavior of confined liquid crystals even for configurations that share similar equilibrium bulk structures.

The Role of Inertia and Dissipation in the Dynamics of the Director for a Nematic Liquid Crystal Coupled with an Electric Field

2015 ◽  
Vol 18 (1) ◽  
pp. 147-166 ◽  
Author(s):  
Peder Aursand ◽  
Johanna Ridder
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Relative Strength ◽  
Inertial Forces ◽  
Director Field ◽  
Voltage Difference ◽  
Electrostatic Equilibrium ◽  
Variational Wave

AbstractWe consider the dynamics of the director in a nematic liquid crystal when under the influence of an applied electric field. Using an energy variational approach we derive a dynamic model for the director including both dissipative and inertial forces.A numerical scheme for the model is proposed by extending a scheme for a related variational wave equation. Numerical experiments are performed studying the realignment of the director field when applying a voltage difference over the liquid crystal cell. In particular, we study how the relative strength of dissipative versus inertial forces influence the time scales of the transition between the initial configuration and the electrostatic equilibrium state.

Sign in / Sign up

Export Citation Format

Share Document