Carbon nanotube dispersion in nematic liquid crystals: An overview

Yadav, Satya Prakash; Singh, Shri

doi:10.1016/j.pmatsci.2015.12.002

Cited by 163 publications

(52 citation statements)

References 195 publications

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“…LC phases provide an attractive route to improve the alignment and packing of nanomaterials, in order to exploit anisotropic properties effectively. LCs of uncharged SWCNTs 416 and graphene 417 dispersions have been reviewed previously. Such systems are very effective for fiber and ordered film production in a wide range of contexts; applications of CCN-derived LCs are covered in section 8.…”

Section: Liquid Crystalsmentioning

confidence: 99%

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

et al. 2018

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Since the discovery of buckminsterfullerene over 30 years ago, sp 2 -hybridised carbon nanomaterials (including fullerenes, carbon nanotubes, and graphene) have stimulated new science and technology across a huge range of fields. Despite the impressive intrinsic properties, challenges in processing and chemical modification continue to hinder applications. Charged carbon nanomaterials (CCNs), formed via the reduction or oxidation of these carbon nanomaterials, facilitate dissolution, purification, separation, chemical modification, and assembly. This approach provides a compelling alternative to traditional damaging and restrictive liquid phase exfoliation routes. The broad chemistry of CCNs not only provides a versatile and potent means to modify the properties of the parent nanomaterial but also raises interesting scientific issues. This review focuses on the fundamental structural forms: buckminsterfullerene, single-walled carbon nanotubes, and single-layer graphene, describing the generation of their respective charged nanocarbon species, their interactions with solvents, chemical reactivity, specific (opto)electronic properties, and emerging applications. CONTENTS

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Section: Liquid Crystalsmentioning

confidence: 99%

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

et al. 2018

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“…For different suspensions the coupling energy of CNTs with the LC matrix, W p , varies over a wide range from 10 −7 N·m −1 [26] to 10 −3 N·m −1 [24]. Assuming a volume fraction of CNTs ≈ 10 −3 [7], we obtain κ ≈ 1, γ ≈ 10 −2 to 10 −1 , σ ≈ 1 to 10 3 and k ≈ 1.…”

Section: Resultsmentioning

confidence: 96%

“…We take typical values for NLCs [36] to estimate dimensionless quantities: χ a ≈ 10 −6 and K 33 > K 11 ≈ 10 −12 N. For CNTs we can assume [7–11]: ≈ 10 −5 to 10 −4 , d ≈ 10 −8 m, CNT length l ≈ 10 −6 m and ν ≈ 10 −22 m −3 . We also set T = 300 K and L = 20 μm.…”

Section: Resultsmentioning

confidence: 99%

“…Along with ferri- or ferromagnetic particles it is also possible to use carbon nanotubes (CNTs) in order to increase the magneto-orientational response of the LC matrix [6–7]. Due to the highly elongated shape (aspect ratios of 10 2 to 10 3 ) and anomalously high anisotropy of the diamagnetic susceptibility ( ≈ 10 −5 to 10 −4 ) [8–11], CNTs are very attractive for the creation of nanocomposites based on LCs with high magneto-orientational response.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes

Petrov¹,

Skokov²,

Zakhlevnykh³

2017

Beilstein J. Nanotechnol.

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We propose a continuum theory of orientational phase transitions induced by an external magnetic field in a suspension of carbon nanotubes in a nematic liquid crystal. It is shown that in a magnetic field a non-uniform and two different uniform phases are possible in the suspension. The uniform phases of the suspension differ by the type of orientational coupling of nanotubes with the liquid crystal matrix (the planar type when the nanotubes are oriented along the matrix director, and the homeotropic type when the nanotubes are perpendicular to the director). The possibility of a redistribution of the nanotube concentration (segregation effect) is shown. The fields of orientational transitions between uniform and non-uniform phases of the suspension are found analytically. It is shown that, when the nanotubes are weakly coupled to the matrix, the magnetic field induces reentrant transitions (uniform planar phase–non-uniform phase–uniform homeotropic phase–non-uniform phase). These transitions can be of first or of second order depending on the carbon nanotubes segregation intensity.

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“…However, current values of electro-optic response times and switch-on voltages still could be (and for some applications need to be) improved. To accomplish this, LCs are being either stabilized by polymers [3] or doped with special materials such as nanotubes [4] and quantum dots [5]. Over the last few years nanoparticles (NPs) have been used to improve the electro-optics properties of LCs as they can influence, for example, the LC response time and decrease the Freedericksz threshold voltage [6–8].…”

Section: Introductionmentioning

confidence: 99%

Thermo- and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles

Siarkowska

Chychłowski

Budaszewski

et al. 2017

Beilstein J. Nanotechnol.

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Thermo- and electro-optical properties of a photonic liquid crystal fiber (PLCF) enhanced by the use of dopants have been investigated. A 6CHBT nematic liquid crystal was doped with four different concentrations of gold nanoparticles (NPs), 0.1, 0.3, 0.5 and 1.0 wt %, for direct comparison of the influence of the dopant on the properties of the PLCF. The thermo-optical effects of the liquid crystal doped with gold NPs were compared in three setups, an LC cell, a microcapillary and within the PLCF, to determine if the observed responses to external factors are caused by the properties of the infiltration material or due to the setup configuration. The results obtained indicated that with increasing NP doping a significant reduction of the rise time under an external electric field occurs with a simultaneous decrease in the nematic–isotropic phase transition temperature, thus improving the thermo- and electro-optical properties of the PLCF.

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Carbon nanotube dispersion in nematic liquid crystals: An overview

Cited by 163 publications

References 195 publications

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes

Thermo- and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles

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