Thermo-, photo-, and mechano-responsive liquid crystal networks enable tunable photonic crystals

Soft Matter ◽  
2017 ◽  
Vol 13 (41) ◽  
pp. 7486-7491 ◽  
Author(s):  
N. Akamatsu ◽  
K. Hisano ◽  
R. Tatsumi ◽  
M. Aizawa ◽  
C. J. Barrett ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Photonic Crystals ◽  
Liquid Crystal Elastomers ◽  
External Stimuli

Tunable photonic crystals exhibiting optical properties that respond reversibly to external stimuli have been developed using liquid crystal networks (LCNs) and liquid crystal elastomers (LCEs).

Electrothermally Driven Fluorescence Switching by Liquid Crystal Elastomers Based On Dimensional Photonic Crystals

2017 ◽  
Vol 9 (13) ◽  
pp. 11770-11779 ◽  
Author(s):  
Changxu Lin ◽  
Yin Jiang ◽  
Cheng-an Tao ◽  
Xianpeng Yin ◽  
Yue Lan ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Photonic Crystals ◽  
Fluorescence Switching ◽  
Liquid Crystal Elastomers

scholarly journals Numerical Methods in Studies of Liquid Crystal Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1650
Author(s):  
Madjid Soltani ◽  
Kaamran Raahemifar ◽  
Arman Nokhosteen ◽  
Farshad Moradi Kashkooli ◽  
Elham L. Zoudani
Keyword(s):  
Liquid Crystal ◽  
Numerical Models ◽  
Future Research ◽  
Artificial Muscles ◽  
Suitable Candidate ◽  
Numerical Studies ◽  
Wide Range ◽  
Electric And Magnetic Fields ◽  
Liquid Crystal Elastomers ◽  
External Stimuli

Liquid crystal elastomers (LCEs) are a type of material with specific features of polymers and of liquid crystals. They exhibit interesting behaviors, i.e., they are able to change their physical properties when met with external stimuli, including heat, light, electric, and magnetic fields. This behavior makes LCEs a suitable candidate for a variety of applications, including, but not limited to, artificial muscles, optical devices, microscopy and imaging systems, biosensor devices, and optimization of solar energy collectors. Due to the wide range of applicability, numerical models are needed not only to further our understanding of the underlining mechanics governing LCE behavior, but also to enable the predictive modeling of their behavior under different circumstances for different applications. Given that several mainstream methods are used for LCE modeling, viz. finite element method, Monte Carlo and molecular dynamics, and the growing interest and reliance on computer modeling for predicting the opto-mechanical behavior of complex structures in real world applications, there is a need to gain a better understanding regarding their strengths and weaknesses so that the best method can be utilized for the specific application at hand. Therefore, this investigation aims to not only to present a multitude of examples on numerical studies conducted on LCEs, but also attempts at offering a concise categorization of different methods based on the desired application to act as a guide for current and future research in this field.

Optical Properties of Liquid Crystal Elastomers

2011 ◽  
Author(s):  
Samriti Khosla ◽  
Suman Lal ◽  
S. K. Tripathi ◽  
Nitin Sood ◽  
Darshan Singh ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystal Elastomers

Tuning the optical properties of planar photonic crystals by liquid crystal infiltration

2005 ◽  
Author(s):  
J. Martz ◽  
B. Wild ◽  
R. Ferrini ◽  
L. A. Dunbar ◽  
M. Mulot ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Photonic Crystals

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.

Optical properties of light-sensitive liquid-crystal elastomers in the vicinity of the nematic-paranematic phase transition

2013 ◽  
Vol 87 (2) ◽  
Author(s):  
Marko Gregorc ◽  
Hui Li ◽  
Valentina Domenici ◽  
Gabriela Ambrožič ◽  
Martin Čopič ◽  
...  
Keyword(s):  
Phase Transition ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystal Elastomers

scholarly journals Stimuli-Responsive Photonic Crystals

2021 ◽  
Vol 11 (5) ◽  
pp. 2119
Author(s):  
Liliana Moscardi ◽  
Guglielmo Lanzani ◽  
Giuseppe M. Paternò ◽  
Francesco Scotognella
Keyword(s):  
Optical Properties ◽  
Photonic Crystals ◽  
Light Emission ◽  
Large Range ◽  
Research Interest ◽  
Stimuli Responsive ◽  
Electrochromic Devices ◽  
Physical Chemical ◽  
Wide Range ◽  
External Stimuli

Recently, tunable photonic crystals (PhCs) have received great research interest, thanks to the wide range of applications in which they can be employed, such as light emission and sensing, among others. In addition, the versatility and ease of fabrication of PhCs allow for the integration of a large range of responsive elements that, in turn, can permit active tuning of PhC optical properties upon application of external stimuli, e.g., physical, chemical or even biological triggers. In this work, we summarize the most employed theoretical tools used for the design of optical properties of responsive PhCs and the most used fabrication techniques. Furthermore, we collect the most relevant results related to this field, with particular emphasis on electrochromic devices.

scholarly journals Light-Actuated Liquid Crystal Elastomer Prepared by Projection Display

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7245
Author(s):  
Juan Chen ◽  
Oluwafemi Isaac Akomolafe ◽  
Jinghua Jiang ◽  
Chenhui Peng
Keyword(s):  
Liquid Crystal ◽  
Three Dimensional ◽  
Topological Defects ◽  
Soft Materials ◽  
Liquid Crystal Elastomer ◽  
Projection Display ◽  
Liquid Crystal Elastomers ◽  
Spatially Varying ◽  
External Stimuli ◽  
3D Shapes

Soft materials with programmability have been widely used in drug delivery, tissue engineering, artificial muscles, biosensors, and related biomedical engineering applications. Liquid crystal elastomers (LCEs) can easily morph into three-dimensional (3D) shapes by external stimuli such as light, heat, and humidity. In order to program two-dimensional (2D) LCE sheets into desired 3D morphologies, it is critical to precisely control the molecular orientations in LCE. In this work, we propose a simple photopatterning method based on a maskless projection display system to create spatially varying molecular orientations in LCE films. By designing different synchronized rotations of the polarizer and projected images, diverse configurations ranging from individual to 2D lattice of topological defects are fabricated. The proposed technique significantly simplified the photopatterning procedure without using fabricated masks or waveplates. Shape transformations such as a cone and a truncated square pyramid, and functionality mimicking the responsive Mimosa Pudica are demonstrated in the fabricated LCE films. The programmable LCE morphing behaviors demonstrated in this work will open opportunities in soft robotics and smart functional devices.

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