Topological Formations in Chiral Nematic Droplets

Posnjak, Gregor

doi:10.1007/978-3-319-98261-8

Cited by 5 publications

(11 citation statements)

References 161 publications

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“…Figure 1(c), (d) show the results of simulations initialised using (2), or its negative (h), throughout the central portion of the droplet and a radial profile outside. The correspondence with experimental observations [19][20][21] is striking, Fig. 1(f), (g) and (j).…”

Section: Chiral Point Defectssupporting

confidence: 82%

“…(4) The correspondence between this local model and experimental observations [20,21] is striking ( Fig. 2(a), (c)), although we find in our simplified director-based simulations that the defect is unstable and breaks apart into two degree −1 defects, each with the Morse-type local structure described above.…”

Section: Singularity Theory and Defects Of Higher Degreesupporting

confidence: 65%

“…In the experiments of Refs. [20,21], typical values were 2 N 6; in the simulations shown here we use values between 2 and 4. We consider a spherical droplet with normal anchoring boundary conditions that has only point defects in the interior.…”

Section: Cholestericsmentioning

confidence: 99%

“…The character of point defects in cholesteric liquid crystals (or magnetic Skyrmion textures) appears not to have been considered previously, apart from recent experimental work realising them [19][20][21]. This contrasts with the situation in nematics where point defects, known colloquially as hedgehogs, have been extensively studied over several decades [2][3][4][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

“…In recent experiments [19][20][21] point defects were created in spherical droplets of cholesteric liquid crystal with normal surface anchoring and shown to have markedly different properties from their nematic counterparts. Whereas spherical nematic droplets relax to a state of minimal distortion with a single defect of degree +1 near the centre and an approximately radial texture [26], a diverse variety of different states were found in the cholesteric case.…”

Section: Introductionmentioning

confidence: 99%

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Point Defects, Topological Chirality, and Singularity Theory in Cholesteric Liquid-Crystal Droplets

et al. 2019

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We develop a theory of point defects in cholesterics and textures in spherical droplets with normal anchoring. The local structure of chiral defects is described by singularity theory and a smecticlike gradient field establishing a nexus between cholesterics and smectics mediated by their defects. We identify the defects of degree −2 and −3 observed experimentally with the singularities D − 4 and T4,4,4, respectively. Radial point defects typical of nematics cannot be perturbed into chiral structures with a single handedness by general topological considerations. For the same reasons, the spherical surface frustrates the chirality in a surface boundary layer containing regions of both handedness.arXiv:1808.03492v1 [cond-mat.soft]

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Section: Chiral Point Defectssupporting

confidence: 82%

Section: Singularity Theory and Defects Of Higher Degreesupporting

confidence: 65%

Section: Cholestericsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Point Defects, Topological Chirality, and Singularity Theory in Cholesteric Liquid-Crystal Droplets

et al. 2019

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Influence of UV light intensity on dielectric behaviours of pure and dye-doped cholesteric liquid crystals

Kocakülah

Yıldırım

Köysal

et al. 2020

J Mater Sci: Mater Electron

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Textural landscapes of VOC-sensitive chiral liquid crystal-based materials

Ramou

Roque²

2023

Applied Physics Reviews

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Liquid crystal-based materials, in which liquid crystal molecules are confined and ordered in compartments, are dynamic materials yielding a variety of optical textures that can be tuned as a response to physical and chemical stimuli. While nematic and smectic-based gel materials have been reported as dynamic optical sensors to report volatile organic compounds (VOCs), chiral systems are less explored despite having the potential to yield extremely rich optical landscapes. Here, we report for the first time the confinement of chiral liquid crystal formulations by an interface formed by ionic liquid molecules. The resultant self-assembled ionic liquid/liquid crystal droplets are simultaneously immobilized on a gelatin matrix. The droplets feature a rich variety of unique topological states. We explored, by means of polarizing optical microscopy, the various droplet optical textures and categorized them with regard to their relative chirality parameter. We further investigated their optical response in the presence of gas analytes and discussed their potential utilization as dynamic liquid crystal-based optical VOC sensors. The newly generated soft materials with semi-selective VOC sensing capabilities can be further utilized in arrays of liquid crystal-based gas sensors for the analysis of complex gas samples using artificial olfaction approaches.

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Topological Formations in Chiral Nematic Droplets

Cited by 5 publications

References 161 publications

Point Defects, Topological Chirality, and Singularity Theory in Cholesteric Liquid-Crystal Droplets

Point Defects, Topological Chirality, and Singularity Theory in Cholesteric Liquid-Crystal Droplets

Influence of UV light intensity on dielectric behaviours of pure and dye-doped cholesteric liquid crystals

Textural landscapes of VOC-sensitive chiral liquid crystal-based materials

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