Domains In Nematic Elastomers

MRS Proceedings ◽

10.1557/proc-328-717 ◽

1993 ◽

Vol 328 ◽

Author(s):

A. Ten Bosch ◽

L. Varichon

Keyword(s):

Liquid Crystal ◽

Mechanical Stress ◽

Stress Tensor ◽

Elastic Deformation ◽

Order Parameter ◽

Side Chain ◽

Elastic Model ◽

Liquid Crystal Elastomer ◽

Nematic Order ◽

Nematic Elastomers

ABSTRACTA theory based on an elastic model and including coupling between elastic deformation and nematic order parameter as well as an interaction between crosslinks and orientation is given. The nematic order parameter and the stress tensor have been determined on elongation and as a function of temperature as well as he anisotropy of the conformation of a side chain liquid crystal elastomer on application of a mechanical stress. A transition from a turbid, low ordered polydomain phase to a transparent, Monodomain is shown to occur.

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Deuteron NMR investigation on orientational order parameter in polymer dispersed liquid crystal elastomers

Physical Chemistry Chemical Physics ◽

10.1039/d0cp04143b ◽

2020 ◽

Vol 22 (40) ◽

pp. 23064-23072

Author(s):

Andraž Rešetič ◽

Jerneja Milavec ◽

Valentina Domenici ◽

Blaž Zupančič ◽

Alexej Bubnov ◽

...

Keyword(s):

Liquid Crystal ◽

Order Parameter ◽

Orientational Order ◽

Orientational Order Parameter ◽

Liquid Crystal Elastomer ◽

H Nmr ◽

Polymer Dispersed Liquid Crystal ◽

Polymer Dispersed ◽

Liquid Crystal Elastomers ◽

Magnetically Aligned

Orientational order parameter of magnetically aligned liquid crystal elastomer particles suspended in a cured silicone matrix is assessed using 2H-NMR spectroscopy. Obtained results correspond well with the composite's thermomechanical response.

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Anomalous Concentration Effects on Phase Behavior and Nematic Order in Mixtures of Side-Chain Liquid Crystal Polymers and Low-Molecular-Weight Liquid Crystals

Macromolecules ◽

10.1021/ma300657s ◽

2012 ◽

Vol 45 (15) ◽

pp. 6220-6229 ◽

Cited By ~ 4

Author(s):

Bilin Zhuang ◽

Zhen-Gang Wang

Keyword(s):

Molecular Weight ◽

Liquid Crystal ◽

Liquid Crystals ◽

Phase Behavior ◽

Side Chain ◽

Liquid Crystal Polymers ◽

Low Molecular Weight ◽

Concentration Effects ◽

Nematic Order

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Nematic liquid crystalline elastomers are aeolotropic materials

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2021.0259 ◽

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.

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Controlled Nanoparticle Targeting and Nanoparticle-Driven Nematic Structural Transition

Advances in Condensed Matter Physics ◽

10.1155/2015/803480 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

A. V. Dubtsov ◽

S. V. Pasechnik ◽

D. V. Shmeliova ◽

S. Kralj ◽

R. Repnik

Keyword(s):

Liquid Crystal ◽

Nematic Liquid Crystal ◽

Order Parameter ◽

Structural Transition ◽

General Mechanism ◽

Type Model ◽

Simple Estimate ◽

Low Concentration ◽

Nematic Order

We study experimentally and theoretically controlled targeting of specific nanoparticles (NPs) to different regions within nematic liquid crystal. Using a simple mesoscopic Landau-de Gennes-type model in terms of a tensor nematic order parameter, we demonstrate a general mechanism which could be exploited for controlled targeting of NPs within a spatially nonhomogeneous nematic texture. Furthermore, we experimentally demonstrate using polarising microscopy that even a relatively low concentration of localised appropriate NPs could trigger a nematic structural transition. A simple estimate is derived to account for the observed transition.

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Mathematical and numerical modeling of liquid crystal elastomer phase transition and deformation

MRS Proceedings ◽

10.1557/opl.2012.249 ◽

2012 ◽

Vol 1403 ◽

Cited By ~ 2

Author(s):

Mariarita de Luca ◽

A. DeSimone

Keyword(s):

Phase Transition ◽

Liquid Crystal ◽

Polymer Chains ◽

Temperature Threshold ◽

Molecular Rearrangement ◽

Liquid Crystal Elastomer ◽

Flexible Polymer ◽

Nematic Elastomers ◽

Linear Version ◽

The One

ABSTRACTLiquid crystal (in particular, nematic) elastomers consist of cross-linked flexible polymer chains with embedded stiff rod molecules that allow them to behave as a rubber and a liquid crystal. Nematic elastomers are characterized by a phase transition from isotropic to nematic past a temperature threshold. They behave as rubber at high temperature and show nematic behavior below the temperature threshold. Such transition is reversible. While in the nematic phase, the rod molecules are aligned along the direction of the ’’nematic director’’. This molecular rearrangement induces a stretch in the polymer chains and hence macroscopic spontaneous deformations. The coupling between nematic order parameter and deformation gives rise to interesting phenomena with a potential for new interesting applications. In the biological field, the ability to considerably change their length makes them very promising as artificial muscles actuators. Their tunable optical properties make them suitable, for example, as lenses for new imaging systems.We present a mathematical model able to describe the behavior of nematic elastomers and numerical simulations reproducing such peculiar behavior. We use a geometrically linear version of the Warner and Terentjev model [1] and consider cooling experiments and stretching experiments in the direction perpendicular to the one of the director at cross-linking.

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