Giant flexoelectricity in bent-core nematic liquid crystal elastomers

2010 ◽  
Vol 96 (10) ◽  
pp. 102907 ◽  
Author(s):  
J. Harden ◽  
M. Chambers ◽  
R. Verduzco ◽  
P. Luchette ◽  
J. T. Gleeson ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Liquid Crystal Elastomers

scholarly journals Better Actuation Through Chemistry: Using Surface Coatings to Create Uniform Director Fields in Nematic Liquid Crystal Elastomers

2016 ◽  
Vol 8 (19) ◽  
pp. 12466-12472 ◽  
Author(s):  
Yu Xia ◽  
Elaine Lee ◽  
Hao Hu ◽  
Mohamed Amine Gharbi ◽  
Daniel A. Beller ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Surface Coatings ◽  
Liquid Crystal Elastomers

scholarly journals Impact damping and vibration attenuation in nematic liquid crystal elastomers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mohand O. Saed ◽  
Waiel Elmadih ◽  
Andrew Terentjev ◽  
Dimitrios Chronopoulos ◽  
David Williamson ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Vibration Isolation ◽  
Surface Adhesion ◽  
Damping Material ◽  
Liquid Crystal Elastomers ◽  
The Impact ◽  
Deformation Modes ◽  
Enhanced Surface ◽  
Impact Damping

AbstractNematic liquid crystal elastomers (LCE) exhibit unique mechanical properties, placing them in a category distinct from other viscoelastic systems. One of their most celebrated properties is the ‘soft elasticity’, leading to a wide plateau of low, nearly-constant stress upon stretching, a characteristically slow stress relaxation, enhanced surface adhesion, and other remarkable effects. The dynamic soft response of LCE to shear deformations leads to the extremely large loss behaviour with the loss factor tanδ approaching unity over a wide temperature and frequency ranges, with clear implications for damping applications. Here we investigate this effect of anomalous damping, optimising the impact and vibration geometries to reach the greatest benefits in vibration isolation and impact damping by accessing internal shear deformation modes. We compare impact energy dissipation in shaped samples and projectiles, with elastic wave transmission and resonance, finding a good correlation between the results of such diverse tests. By comparing with ordinary elastomers used for industrial damping, we demonstrate that the nematic LCE is an exceptional damping material and propose directions that should be explored for further improvements in practical damping applications.

Nonlocal model for nematic liquid-crystal elastomers

2006 ◽  
Vol 74 (6) ◽  
Author(s):  
R. Ennis ◽  
L. C. Malacarne ◽  
P. Palffy-Muhoray ◽  
M. Shelley
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Nonlocal Model ◽  
Liquid Crystal Elastomers

Effect of molecular parameters on thermomechanical behavior of side-on nematic liquid crystal elastomers

Polymer ◽  
2013 ◽  
Vol 54 (20) ◽  
pp. 5321-5329 ◽  
Author(s):  
Renbo Wei ◽  
Lingyun Zhou ◽  
Yaning He ◽  
Xiaogong Wang ◽  
Patrick Keller
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Thermomechanical Behavior ◽  
Molecular Parameters ◽  
Liquid Crystal Elastomers

scholarly journals Study of the optical, thermal, and mechanical properties of nematic liquid crystal elastomers

2016 ◽  
Vol 17 (4) ◽  
pp. 169-176 ◽  
Author(s):  
Santosh A. Mani ◽  
Sameer U. Hadkar ◽  
P. J. Jessy ◽  
Suman Lal ◽  
Patrick Keller ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Thermal And Mechanical Properties ◽  
Liquid Crystal Elastomers

scholarly journals Instabilities in liquid crystal elastomers

MRS Bulletin ◽  
2021 ◽  
Author(s):  
L. Angela Mihai ◽  
Alain Goriely
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Void Nucleation ◽  
Stochastic Methods ◽  
Model Parameters ◽  
Homogeneous State ◽  
Mechanical Effects ◽  
Liquid Crystal Elastomers ◽  
External Stimuli ◽  
Constitutive Parameters

AbstractStability is an important and fruitful avenue of research for liquid crystal elastomers. At constant temperature, upon stretching, the homogeneous state of a nematic body becomes unstable, and alternating shear stripes develop at very low stress. Moreover, these materials can experience classical mechanical effects, such as necking, void nucleation and cavitation, and inflation instability, which are inherited from their polymeric network. We investigate the following two problems: First, how do instabilities in nematic bodies change from those found in purely elastic solids? Second, how are these phenomena modified if the material constants fluctuate? To answer these questions, we present a systematic study of instabilities occurring in nematic liquid crystal elastomers, and examine the contribution of the nematic component and of fluctuating model parameters that follow probability laws. This combined analysis may lead to more realistic estimations of subsequent mechanical damage in nematic solid materials. Because of their complex material responses in the presence of external stimuli, liquid crystal elastomers have many potential applications in science, manufacturing, and medical research. The modeling of these materials requires a multiphysics approach, linking traditional continuum mechanics with liquid crystal theory, and has led to the discovery of intriguing mechanical effects. An important problem for both applications and our fundamental understanding of nematic elastomers is their instability under large strains, as this can be harnessed for actuation, sensing, or patterning. The goal is then to identify parameter values at which a bifurcation emerges, and how these values change with external stimuli, such as temperature or loads. However, constitutive parameters of real manufactured materials have an inherent variation that should also be taken into account, thus the need to quantify uncertainties in physical responses, which can be done by combining the classical field theories with stochastic methods that enable the propagation of uncertainties from input data to output quantities of interest. The present study demonstrates how to characterize instabilities found in nematic liquid crystal elastomers with probabilistic material parameters at the macroscopic scale, and paves the way for a systematic theoretical and experimental study of these fascinating materials.

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