Graphene as an alignment agent, an electrode, and a source of surface chirality in a smectic-
<i>A</i>
 liquid crystal

Basu, Rajratan

doi:10.1103/physreve.103.022710

Cited by 8 publications

(3 citation statements)

References 43 publications

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“…This interaction ensures that the NLC achieves a uniform planar-aligned state over a large-scale dimension on graphene [25]. The hexagonal graphene lattice, with a C-C bond length of 1.42 Å, closely mirrors the hexagonal benzene ring with a C-C bond length of 1.40 Å [26]. This near-identical size facilitates the coherent alignment of NLC molecules on the 2D graphene surface due to epitaxial interactions [28][29][30] between the benzene rings of the NLC molecules and the hexagonal lattice of graphene.…”

Section: Introductionmentioning

confidence: 97%

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Alignment of Nematic Liquid Crystal 5CB Using Graphene Oxide

Politano,

Filice,

Versace

2023

Crystals

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In this article, we employed the saturation voltage method (SVM) to investigate the interaction between a nematic liquid crystal (NLC) and a graphene oxide (GO) substrate. The SVM approach involved applying a potential difference (ΔV) to the cell containing the NLC (specifically, 5CB) to reorient the nematic director (n) from a parallel to a perpendicular configuration with respect to the cell’s surface. By utilizing sandwich cells with indium–tin oxide semi-transparent electrodes covered by GO, we measured the anchoring energy between the NLC and the thin GO film. To evaluate the strength of this anchoring energy, we compared the results with two other cells: one exhibiting strong anchoring energy (polyimide cell) and the other demonstrating weak anchoring energy (formvar cell). The influence of GO thin films on the alignment of nematic 5CB was distinctly observed.

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Section: Introductionmentioning

confidence: 97%

“…Graphene's potential extends beyond just interactions with NLCs. It can serve as both electrodes and aligning layers in liquid crystal devices, enhancing their performance [26]. Traditional NLC cells use polyimide-coated surfaces [27] with unidirectional rubbing to determine the NLC's nematic director profile.…”

Section: Introductionmentioning

confidence: 99%

Alignment of Nematic Liquid Crystal 5CB Using Graphene Oxide

Politano,

Filice,

Versace

2023

Crystals

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“…Toward puri cation, nanomaterials need to be surface-treated leading to their effective role within LCs. Graphene (Gr) is one of the well-known 2D nanomaterials that can manipulate the electrical properties of LCs 22,23,[32][33][34][24][25][26][27][28][29][30][31] . The effectiveness of Gr layers in different phases of LCs often leads to two outcomes: (I) When Gr sheets mix with LC, their electrostatic eld leads to the suppression of ionic behaviors such as reduction in ionic density, diffusivity, and relaxation frequency through the ion trapping/charge annihilation process 21 ; (II) The interaction between the honeycomb pattern of Gr and the benzene rings of LC molecules causes the LC directors to planar stabilize on the surface of the Gr layers and results in the improvement of dielectric anisotropy 35 .…”

Section: Introductionmentioning

confidence: 99%

Enhancement in ionic conductivity of liquid crystals by graphene/metal-oxide-nanocomposite

Khodaee

Dalir

Feghhi

et al. 2023

Preprint

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Enhancing the ionic conductivity of liquid crystal (LC) circumvents challenges for application in advanced electronic components. Toward this, using additives made of different nanostructures that could result in functional LCs is suggested. In this paper, various concentrations of graphene (Gr)/metal-oxide (Fe3O4) nanocomposite (GMN) (0.0001-1 w%) were added to E7 nematic LC. We found that the role of anisotropic Gr flakes, their edges as well as surface-decorated-metal-oxide-additives have significant impact on electrical properties of E7. A range of appropriate additives of such a nanocomposite enhances the electrical conductivity of LCs. This effect can be traced through the decrease in the formation of GMN aggregates in the E7 and increase in the electrostatic field at the edges of the Gr sheets. Moreover, the presence of metal-oxide nanoclusters due to the presence of oxygen vacancies and defects facilitates the construction of conductive network for improving the charge transfer pathways and contributes to a stronger interaction of the Gr surface with charged species. These factors can provide Gr layers as dipole moments and lead to signal propagation in the dielectric medium. Our finding conveys a pathway toward significant enhancement of ionic conductivity in the LC family which can be useful for functional applications.

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Photo‐Actuated Chiral Smectic Superstructures

Cao

et al. 2022

Advanced Optical Materials

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Chirality and hierarchy are two representative features of complex configurations inspiring exotic functions. Chiral additives are adopted to break the mirror symmetry of molecular orientation inside smectic layers, and overcome the restriction on in‐layer helical arrangement by virtue of the surface electroclinic effect. The chirality strength of liquid crystals is regulated via the photo‐isomerization of chiral molecular switch, the doping concentration control, and the mixing of different chiral additives. The dynamic evolution of chiral smectic superstructures leads to the reversible rotation of oily streaks (OSs), and even structural transformation between OSs and focal conic domains is demonstrated. This releases new freedom of chiral hierarchical configurations and may inspire fantastic applications in active optics, sensing, and micro‐manufacturing.

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Graphene as an alignment agent, an electrode, and a source of surface chirality in a smectic- A liquid crystal

Cited by 8 publications

References 43 publications

Alignment of Nematic Liquid Crystal 5CB Using Graphene Oxide

Alignment of Nematic Liquid Crystal 5CB Using Graphene Oxide

Enhancement in ionic conductivity of liquid crystals by graphene/metal-oxide-nanocomposite

Photo‐Actuated Chiral Smectic Superstructures

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