scholarly journals The effect of liquid crystalline graphene oxide compared with non-liquid crystalline graphene oxide on the rheological properties of polyacrylonitrile solution

2021 ◽  
Vol 40 (1) ◽  
pp. 428-438
Author(s):  
Baihua Liu ◽  
Cong Wang ◽  
Yu Muhuo
Keyword(s):  
Graphene Oxide ◽  
Liquid Crystal ◽  
Rheological Properties ◽  
Liquid Crystalline ◽  
Viscosity Index ◽  
Low Frequency ◽  
Liquid Crystallinity ◽  
Liquid Crystal System ◽  
Liquid Crystal Property ◽  
Polyacrylonitrile Solution

Abstract In this article, polyacrylonitrile (PAN) and two kinds of graphene oxide (GO) with different structural properties are blended in dimethyl sulfoxide (DMSO) according to a certain ratio to prepare stable-spinning solution. One kind of GO is purchased, and we call it GO1. The other is a kind of self-made GO with liquid crystal property in solution, which is called GO2. The effects of two kinds of GO on the rheological properties of PAN/GO spinning solution (15 wt%) were studied. The results show that the viscous activation energy of the liquid crystal GO2/PAN blend solution is significantly higher than that of the nonliquid crystal GO1/PAN blend solution. Moreover, the liquid crystal system is more obviously affected by temperature. The structural viscosity index of the liquid crystalline GO2/PAN solution is obviously lower than that of the GO1/PAN solution. It indicates that the existence of liquid crystallinity is beneficial to the spinning of the solution. In the low-frequency region, the addition of GO1 makes the solution more elastic, and the addition of GO2 makes the solution more viscous.

scholarly journals Engineering Achiral Liquid Crystalline Polymers for Chiral Self-Recovery

2021 ◽  
Vol 22 (21) ◽  
pp. 11980
Author(s):  
Tengfei Miao ◽  
Xiaoxiao Cheng ◽  
Yilin Qian ◽  
Yaling Zhuang ◽  
Wei Zhang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Uv Light ◽  
Helical Structure ◽  
Side Chain ◽  
Liquid Crystal Polymers ◽  
Polymeric Liquid ◽  
Crystalline Polymers ◽  
Liquid Crystal System ◽  
And Storage

Flexible construction of permanently stored supramolecular chirality with stimulus-responsiveness remains a big challenge. Herein, we describe an efficient method to realize the transfer and storage of chirality in intrinsically achiral films of a side-chain polymeric liquid crystal system by combining chiral doping and cross-linking strategy. Even the helical structure was destroyed by UV light irradiation, the memorized chiral information in the covalent network enabled complete self-recovery of the original chiral superstructure. These results allowed the building of a novel chiroptical switch without any additional chiral source in multiple types of liquid crystal polymers, which may be one of the competitive candidates for use in stimulus-responsive chiro-optical devices.

Tuning the structure, thermal stability and rheological properties of liquid crystal phases via the addition of silica nanoparticles

2019 ◽  
Vol 21 (46) ◽  
pp. 25649-25657 ◽  
Author(s):  
Joshua B. Marlow ◽  
Thomas M. McCoy ◽  
Cat Q. Ho ◽  
Liliana de Campo ◽  
Robert Knott ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Liquid Crystal ◽  
Light Microscopy ◽  
Surface Chemistry ◽  
Silica Nanoparticles ◽  
Rheological Properties ◽  
Small Angle ◽  
Angle Scattering ◽  
Liquid Crystal System ◽  
Crystal Phases

The effects of adding silica nanoparticles of varying size and surface chemistry to a liquid crystal system were analysed using small-angle scattering and polarising light microscopy, with varying temperature and applied shear.

SIDE CHAIN LIQUID CRYSTAL POLYMERS FOR QUADRATIC NONLINEAR OPTICS

1996 ◽  
Vol 05 (04) ◽  
pp. 735-755 ◽  
Author(s):  
D. GONIN ◽  
B. GUICHARD ◽  
M.C.J. LARGE ◽  
T. DANTAS DE MORAIS ◽  
C. NOËL ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Statistical Models ◽  
Liquid Crystalline ◽  
Nonlinear Optical ◽  
Side Chain ◽  
Liquid Crystal Polymers ◽  
Mesogenic Group ◽  
Liquid Crystallinity ◽  
Polar Order

In this paper we consider the behavior of a number of side chain liquid crystal polymers having the same mesogenic group and relate their liquid crystalline behavior to their polarization and nonlinear optical properties. We show that the liquid crystallinity of the materials results in an enhancement of the polar order over that of isotropic materials, in qualitative agreement with molecular statistical models.

scholarly journals Dynamic assembly of liquid crystalline graphene oxide gel fibers for ion transport

2018 ◽  
Vol 4 (11) ◽  
pp. eaau2104 ◽  
Author(s):  
H. Park ◽  
K. H. Lee ◽  
Y. B. Kim ◽  
S. B. Ambade ◽  
S. H. Noh ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Liquid Crystalline ◽  
Colloidal Dispersions ◽  
Charge Carriers ◽  
Wet Spinning ◽  
Great Promise ◽  
Orientation Factor ◽  
Liquid Crystallinity ◽  
Spinning Process ◽  
Dynamic Assembly

Colloidal dispersions with liquid crystallinity hold great promise for fabricating their superstructures. As an example, when graphene oxide (GO) sheets are assembled in the liquid crystalline state, they can turn into ordered macroscopic forms of GO such as fibers via the wet spinning process. Here, we report that by reinforcing intersheet interactions, GO liquid crystals (LCs) turn into mechanically robust hydrogels that can be readily drawn into highly aligned fibrillar structures. GO hydrogel fibers with highly aligned sheets (orientation factor, f = 0.71) exhibit more than twice the ionic conductivity compared to those with partially aligned structures (f = 0.01). The hierarchically interconnected two-dimensional nanochannels within these neatly aligned GOLC hydrogel fibers may facilitate controlled transport of charge carriers and could be potentially explored as cables for interconnecting biosystems and/or human-made devices.

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.

Hybrid molecular/mineral lyotropic liquid crystal system of CTAB and graphene oxide in water

Carbon ◽  
2021 ◽  
Vol 173 ◽  
pp. 105-114
Author(s):  
Yizhen Shao ◽  
Maria Iliut ◽  
Ingo Dierking ◽  
Aravind Vijayaraghavan
Keyword(s):  
Graphene Oxide ◽  
Liquid Crystal ◽  
Lyotropic Liquid Crystal ◽  
Crystal System ◽  
Liquid Crystal System

Measurement of the dielectric properties of various monoolein/ water mesophases between 90 and 140 GHz

2020 ◽  
Vol 62 (11) ◽  
pp. 1118-1120
Author(s):  
Chuang Yang ◽  
Jian Wang
Keyword(s):  
Liquid Crystal ◽  
Dielectric Properties ◽  
Millimeter Wave ◽  
Low Frequency ◽  
Imaginary Component ◽  
Sample Holder ◽  
Crystal System ◽  
Transmission Parameters ◽  
Liquid Crystal System ◽  
Ieee Standard

Abstract In this paper, the dielectric properties of a series of glyceryl monoolein/ water liquid crystal systems containing 15, 20, 25, 30, 35, 40, 45, and 50 wt.-% water are measured between 90 and 140 GHz. An IEEE standard WR-08 waveguide shim is used as a sample holder. The holder is filled with the monoolein/water liquid crystal system during measurement. The S-parameters of the sample holder filled with the liquid crystal systems are measured using 90-140 GHz millimeter-wave test equipment. The dielectric properties of the crystal systems are extracted from the measured transmission parameters (S21) using the Newton algorithm. We find that the dielectric properties of these glyceryl monoolein/water liquid crystal systems from 90 GHz to 140 GHz are not sensitive to frequency. That is in contrast to the low-frequency dielectric properties in the literature. We also find that the imaginary component of the dielectric spectroscopy between 90 and 140 GHz can identify the phase of the monoolein/water liquid crystal system. The finds in this paper are important for monoolein study.

Rheological properties of graphene oxide liquid crystal

Carbon ◽  
2014 ◽  
Vol 80 ◽  
pp. 453-461 ◽  
Author(s):  
Pradip Kumar ◽  
Uday Narayan Maiti ◽  
Kyung Eun Lee ◽  
Sang Ouk Kim
Keyword(s):  
Graphene Oxide ◽  
Liquid Crystal ◽  
Rheological Properties

Dielectric Relaxation Studies of Silver Nanoparticles dispersed Liquid Crystal

2015 ◽  
Vol 8 (3) ◽  
pp. 2176-2188 ◽  
Author(s):  
Keisham Nanao Singh
Keyword(s):  
Activation Energy ◽  
Silver Nanoparticles ◽  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Relaxation Process ◽  
Relaxation Times ◽  
Low Frequency ◽  
Bulk Liquid ◽  
Molecular Rearrangement ◽  
Relaxation Studies

This article reports on the Dielectric Relaxation Studies of two Liquid Crystalline compounds - 7O.4 and 7O.6 - doped with dodecanethiol capped Silver Nanoparticles. The liquid crystal molecules are aligned homeotropically using CTAB. The low frequency relaxation process occurring above 1 MHz is fitted to Cole-Cole formula using the software Dielectric Spectra fit. The effect of the Silver Nanoparticles on the molecular dipole dynamics are discussed in terms of the fitted relaxation times, Cole-Cole distribution parameter and activation energy. The study indicate a local molecular rearrangement of the liquid crystal molecules without affecting the order of the bulk liquid crystal molecules but these local molecules surrounding the Silver Nanoparticles do not contribute to the relaxation process in the studied frequency range. The observed effect on activation energy suggests a change in interaction between the nanoparticles/liquid crystal molecules.

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