STRAIN-ORDER COUPLING IN NEMATIC ELASTOMERS: EQUILIBRIUM CONFIGURATIONS

2009 ◽  
Vol 19 (04) ◽  
pp. 601-630 ◽  
Author(s):  
PIERLUIGI CESANA ◽  
ANTONIO DESIMONE
Keyword(s):  
Liquid Crystal ◽  
Boundary Conditions ◽  
Phase Diagrams ◽  
Static Equilibrium ◽  
Explicit Solutions ◽  
Special Boundary ◽  
Equilibrium Solutions ◽  
Nematic Elastomers ◽  
Equilibrium Configurations ◽  
Liquid Crystal Elastomers

We consider models that describe liquid crystal elastomers either in a biaxial or in a uniaxial phase and in the framework of Frank's director theory. We prove the existence of static equilibrium solutions in the presence of frustrations due to electro-mechanical boundary conditions and to applied loads and fields. We find explicit solutions arising in connection with special boundary conditions and the corresponding phase diagrams, leading to significant implications on possible experimental observations.

scholarly journals Nematic liquid crystalline elastomers are aeolotropic materials

2021 ◽  
Vol 477 (2253) ◽  
pp. 20210259
Author(s):  
L. Angela Mihai ◽  
Haoran Wang ◽  
Johann Guilleminot ◽  
Alain Goriely
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Additional Term ◽  
Elastic Response ◽  
Order Effects ◽  
Nematic Order ◽  
Nematic Elastomers ◽  
Strain Limit ◽  
Liquid Crystal Elastomers ◽  
Dynamics Simulations

Continuum models describing ideal nematic solids are widely used in theoretical studies of liquid crystal elastomers. However, experiments on nematic elastomers show a type of anisotropic response that is not predicted by the ideal models. Therefore, their description requires an additional term coupling elastic and nematic responses, to account for aeolotropic effects. In order to better understand the observed elastic response of liquid crystal elastomers, we analyse theoretically and computationally different stretch and shear deformations. We then compare the elastic moduli in the infinitesimal elastic strain limit obtained from the molecular dynamics simulations with the ones derived theoretically, and show that they are better explained by including nematic order effects within the continuum framework.

Mechano‐Optical Sensors Fabricated with Multilayered Liquid Crystal Elastomers Exhibiting Tunable Deformation Recovery

2021 ◽  
pp. 2104702
Author(s):  
Kyohei Hisano ◽  
Seiya Kimura ◽  
Kyosun Ku ◽  
Tomoki Shigeyama ◽  
Norihisa Akamatsu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Optical Sensors ◽  
Liquid Crystal Elastomers ◽  
Deformation Recovery

Thermomechanically active electrodes power work-dense soft actuators

Soft Matter ◽  
2021 ◽  
Author(s):  
Angel Martinez ◽  
Arul Clement ◽  
Junfeng Gao ◽  
Julia Kocherzat ◽  
Mohsen Tabrizi ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Metal ◽  
Chain Extender ◽  
Design Work ◽  
Liquid Crystal Elastomers ◽  
Soft Actuators ◽  
Dense Liquid

The effect of chain extender structure and composition on the properties of liquid crystal elastomers (LCE) is presented. Compositions are optimized to design work-dense liquid metal LCE composites that are operated with 100 mW power.

scholarly journals Internal constraints and arrested relaxation in main-chain nematic elastomers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Takuya Ohzono ◽  
Kaoru Katoh ◽  
Hiroyuki Minamikawa ◽  
Mohand O. Saed ◽  
Eugene M. Terentjev
Keyword(s):  
Mechanical Properties ◽  
Main Chain ◽  
Polymer Networks ◽  
Nematic Order ◽  
Nematic Elastomers ◽  
Nematic Director ◽  
Highly Nonlinear ◽  
Nonlinear Mechanical ◽  
Liquid Crystal Elastomers ◽  
Memory Applications

AbstractNematic liquid crystal elastomers (N-LCE) exhibit intriguing mechanical properties, such as reversible actuation and soft elasticity, which manifests as a wide plateau of low nearly-constant stress upon stretching. N-LCE also have a characteristically slow stress relaxation, which sometimes prevents their shape recovery. To understand how the inherent nematic order retards and arrests the equilibration, here we examine hysteretic stress-strain characteristics in a series of specifically designed main-chain N-LCE, investigating both macroscopic mechanical properties and the microscopic nematic director distribution under applied strains. The hysteretic features are attributed to the dynamics of thermodynamically unfavoured hairpins, the sharp folds on anisotropic polymer strands, the creation and transition of which are restricted by the nematic order. These findings provide a new avenue for tuning the hysteretic nature of N-LCE at both macro- and microscopic levels via different designs of polymer networks, toward materials with highly nonlinear mechanical properties and shape-memory applications.

Effect of stretching angle on the stress plateau behavior of main-chain liquid crystal elastomers

Soft Matter ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. 3128-3136
Author(s):  
Suzuka Okamoto ◽  
Shinichi Sakurai ◽  
Kenji Urayama
Keyword(s):  
Liquid Crystal ◽  
Main Chain ◽  
Stress Plateau ◽  
Liquid Crystal Elastomer ◽  
Ultimate Elongation ◽  
Liquid Crystal Elastomers

Stretching angle for a main-chain liquid crystal elastomer has pronounced effects on the width of the stress plateau as well as the ultimate elongation, while it has no effect on the plateau height.

Healable and Rearrangeable Networks of Liquid Crystal Elastomers Enabled by Diselenide Bonds

2021 ◽  
Author(s):  
Ling Chen ◽  
Hari Bisoyi ◽  
Yinliang Huang ◽  
Shuai Huang ◽  
Meng Wang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystal Elastomers
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