Electric-Field Effects in Dilute Suspensions of Carbon Nanotubes Dispersed in Nematic Liquid Crystals

2010 ◽  
Vol 428-429 ◽  
pp. 173-181 ◽  
Author(s):  
Muklesur Rahman ◽  
Wei Lee
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystal ◽  
Carbon Nanotube ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Colloidal Particles ◽  
Liquid Crystal Display ◽  
New Physics ◽  
Colloidal System ◽  
Colloidal Systems

Colloids composed of liquid-crystal hydrosols exhibit a rich set of interesting phenomena. The coupling between liquid-crystalline media and colloidal particles plays an essential role leading to an abundant source of new physics. In the last few years, peculiar behaviors of carbon-nanotube-doped calamitic liquid crystals have attracted considerable attention. This paper provides a brief introduction to this alluring subject for its on-going research development in this laboratory. First presented are our current understandings of the nematic colloidal system comprising carbon nanotubes and of their possible orientation and dynamics under the application of an external field. Various electro-optical and electrical properties of a liquid-crystal display rectified by the nanoscale carbonaceous guest are then addressed to a larger extent. Dielectric relaxation obtained from a nematic impregnated with carbon nanotubes is also discussed. With historical significance for the dawn of the liquid-crystal–carbon-nanotube research, several important findings of enhanced nonlinear optical properties in typical nematic mesomaterials consisting of suspended nanotubes are delineated. With the new colloidal systems of elongated nanoscale solids dispersed in anisotropic fluids in the mesophase, many new intriguing phenomena are awaiting theoretical and experimental explorations. Collaborations are called to draw attention of interested theoretical physicists, in particular.

scholarly journals Lyotropic Liquid Crystals from Colloidal Suspensions of Graphene Oxide

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 455 ◽  
Author(s):  
Adam P. Draude ◽  
Ingo Dierking
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Colloidal Particles ◽  
Colloidal Suspensions ◽  
Lyotropic Liquid Crystals ◽  
Nanoscience And Nanotechnology ◽  
And Behavior

Lyotropic liquid crystals from colloidal particles have been known for more than a century, but have attracted a revived interest over the last few years. This is due to the developments in nanoscience and nanotechnology, where the liquid crystal order can be exploited to orient and reorient the anisotropic colloids, thus enabling, increasing and switching the preferential properties of the nanoparticles. In particular, carbon-based colloids like carbon nanotubes and graphene/graphene–oxide have increasingly been studied with respect to their lyotropic liquid crystalline properties over the recent years. We critically review aspects of lyotropic graphene oxide liquid crystal with respect to properties and behavior which seem to be generally established, but also discuss those effects that are largely unfamiliar so far, or as of yet of controversial experimental or theoretical outcome.

scholarly journals Bidirectional rotation control of a carbon fiber in nematic liquid crystal using AC electric field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jun-Yong Lee ◽  
Jeong-Seon Yu ◽  
Jong-Hyun Kim
Keyword(s):  
Free Energy ◽  
Liquid Crystal ◽  
Electric Field ◽  
Colloidal Particles ◽  
Colloidal System ◽  
Wide Angle ◽  
Local Minima ◽  
Free Energies ◽  
Rotation Direction ◽  
Ac Electric Field

Abstract Colloidal particles dispersed in nematic liquid crystals are aligned along the orientation that minimizes the elastic free energy. Through applying an electric field to a nematic colloidal system, the orientation of the director can change. Consequently, colloidal particles realign to minimize the total free energy, which is the sum of the elastic and electric free energies. Herein, we demonstrate that if the preferred rotation directions given by the electric and elastic free energies are different during realignment, the rotation direction of the particle can be controlled by how we apply the electric field. When the strength of the electric field gradually increases, the particles rotate in the same direction as the rotation of the director. However, when a sufficiently high electric field is suddenly applied, the particles rotate in the opposite direction. In this study, we analyzed the effect of free energy on the bidirectional rotation behavior of the particles using a theoretical model. This study provides an effective approach to control the rotational behavior of colloidal particles over a wide-angle range between two orientational local minima.

scholarly journals Anomalous Long-Range Attraction in Colloidal Binary Mixtures at Fluid–Fluid Interfaces

2020 ◽  
Vol 4 (3) ◽  
pp. 36
Author(s):  
Zonglin Yi ◽  
To Ngai
Keyword(s):  
Long Range ◽  
Colloidal Particles ◽  
Experimental Result ◽  
Colloidal System ◽  
Fluid Interfaces ◽  
Water Interface ◽  
Two Dimensional ◽  
Colloidal Systems ◽  
Oil Water ◽  
Theoretical Side

The properties of binary colloidal systems have gained the interest of researchers because they have much richer structures than their one-component counterpart. Continuing efforts are being made on the theoretical side on binary colloidal systems, while many issues remained unsolved for the lack of solid experimental supports, especially for study in the field of two-dimensional (2D) binary colloids system. Oil–water interfaces can serve as a good stringent 2D confinement for colloidal particles and can avoid anomalous problems caused by the quasi-two-dimensional environment in previous experimental reports. In this work, we conduct experimental research of binary colloids system in an oil–water interface to revisit theoretical predication. We measure an ultra-long-range attraction and discuss the possible mechanism of this attraction by comparing the experimental result with existing model and theory. This study could contribute more understanding of the binary colloidal system in both experimental aspects and theoretical aspects.

Ideal Liquid Crystal Display Mode Using Achiral Banana-Shaped Liquid Crystals

2006 ◽  
Vol 45 (No. 10) ◽  
pp. L282-L284 ◽  
Author(s):  
Yoshio Shimbo ◽  
Yoichi Takanishi ◽  
Ken Ishikawa ◽  
Ewa Gorecka ◽  
Damian Pociecha ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystal Display ◽  
Ideal Liquid ◽  
Display Mode

Antiferroelectric Liquid Crystals from Achiral Molecules And A Liquid Conglomerate

1999 ◽  
Vol 559 ◽  
Author(s):  
David M. Walba ◽  
Eva Körblova ◽  
Renfan Shao ◽  
Joseph E. Maclennan ◽  
Darren R. Link ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Crystalline Structures ◽  
Chiral Liquid Crystal ◽  
Antiferroelectric Liquid Crystals ◽  
Liquid Crystal Structure

ABSTRACTUntil recently, it was an empirical fact that creation of a chiral liquid crystal phase required enantiomerically enriched molecules. In addition, to date known ferroelectric and antiferroelectric smectics have also been composed of enantiomerically enriched molecules. Herein are described the first examples of the formation of chiral and antiferroelectric supermolecular liquid crystalline structures from achiral molecules. In one case (apparently metastable) the liquid crystal structure is macroscopically chiral, with samples composed of heterochiral macroscopic domains: a liquid conglomerate.

Hierarchical Assembly of Carbon Nanotubes-Liquid Crystal Nanocomposite

2008 ◽  
Vol 8 (4) ◽  
pp. 1735-1740
Author(s):  
Sudarshan Kundu ◽  
Sudip K. Batabyal ◽  
Prasenjit Nayek ◽  
Subir K. Roy
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Nanocomposite Materials ◽  
Sem Analysis ◽  
Ferroelectric Liquid Crystal ◽  
Multiwalled Carbon ◽  
Hierarchical Assembly ◽  
Ac Electrical Properties

Fabrication of liquid crystalline (LC) nanomaterials in an aligned pattern along the multiwalled carbon nanotubes (CNT) has been reported here. The nanocomposite was prepared by sonicating esterified CNTs and the ferroelectric liquid crystal (FLC) in chloroform. The nanohybrid shish kebab (NHSK) like pattern was observed in SEM analysis. The nanocomposite materials were characterized by Fourier transform infrared spectroscopy (FTIR), polarizing optical microscopy and electron microscopy. The DC and AC electrical properties of the composite materials were investigated. The DC conductivity of the nanocomposite increased by 2 order from the FLC materials and AC relaxation has been observed, in the nanocomposite, which was totally absent in the FLC materials.

scholarly journals Functional Smart Dispersed Liquid Crystals for Nano- and Biophotonic Applications: Nanoparticles-Assisted Optical Bioimaging

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
N. V. Kamanina ◽  
S. V. Likhomanova ◽  
Yu. A. Zubtcova ◽  
A. A. Kamanin ◽  
A. Pawlicka
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Solid Substrate ◽  
Holographic Recording ◽  
Self Assembling ◽  
Aligned Carbon Nanotubes ◽  
Vertically Aligned ◽  
Crystal Cells ◽  
Modified Functional

Functional nematic liquid crystal structures doped with nano- and bioobjects have been investigated. The self-assembling features and the photorefractive parameters of the structured liquid crystals have been comparatively studied via microscopy and laser techniques. Fullerene, quantum dots, carbon nanotubes, DNA, and erythrocytes have been considered as the effective nano- and biosensitizers of the LC mesophase. The holographic recording technique based on four-wave mixing of the laser beams has been used to investigate the laser-induced change of the refractive index in the nano- and bioobjects-doped liquid crystal cells. The special accent has been given to novel nanostructured relief with vertically aligned carbon nanotubes at the interface: solid substrate-liquid crystal mesophase. It has been shown that this nanostructured relief influences the orienting ability of the liquid crystal molecules with good advantage. As a result, it provokes the orientation of the DNA. The modified functional liquid crystal materials have been proposed as the perspective systems for both the photonics and biology as well as the medical applications.

Sign in / Sign up

Export Citation Format

Share Document