Periodic assembly of nanoparticle arrays in disclinations of cholesteric liquid crystals

An important goal of the modern soft matter science is to discover new self-assembly modalities to precisely control the placement of small particles in space. Spatial inhomogeneity of liquid crystals offers the capability to organize colloids in certain regions such as the cores of the topological defects. Here we report two self-assembly modes of nanoparticles in linear defects-disclinations in a lyotropic colloidal cholesteric liquid crystal: a continuous helicoidal thread and a periodic array of discrete beads. The beads form one-dimensional arrays with a periodicity that matches half a pitch of the cholesteric phase. The periodic assembly is governed by the anisotropic surface tension and elasticity at the interface of beads with the liquid crystal. This mode of self-assembly of nanoparticles in disclinations expands our ability to use topological defects in liquid crystals as templates for the organization of nanocolloids.

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Topological liquid crystal superstructures as structured light lasers

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2110839118 ◽

2021 ◽

Vol 118 (49) ◽

pp. e2110839118

Author(s):

Miha Papič ◽

Urban Mur ◽

Kottoli Poyil Zuhail ◽

Miha Ravnik ◽

Igor Muševič ◽

...

Keyword(s):

Self Assembly ◽

Soft Matter ◽

Structured Light ◽

Topological Defects ◽

Photonic Devices ◽

Light Polarization ◽

Self Healing ◽

Fabry Perot ◽

Self Assembled ◽

External Stimuli

Liquid crystals (LCs) form an extremely rich range of self-assembled topological structures with artificially or naturally created topological defects. Some of the main applications of LCs are various optical and photonic devices, where compared to their solid-state counterparts, soft photonic systems are fundamentally different in terms of unique properties such as self-assembly, self-healing, large tunability, sensitivity to external stimuli, and biocompatibility. Here we show that complex tunable microlasers emitting structured light can be generated from self-assembled topological LC superstructures containing topological defects inserted into a thin Fabry–Pérot microcavity. The topology and geometry of the LC superstructure determine the structuring of the emitted light by providing complex three-dimensionally varying optical axis and order parameter singularities, also affecting the topology of the light polarization. The microlaser can be switched between modes by an electric field, and its wavelength can be tuned with temperature. The proposed soft matter microlaser approach opens directions in soft matter photonics research, where structured light with specifically tailored intensity and polarization fields could be designed and implemented.

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Control of the Induced Handedness of Helical Nanofilaments Employing Cholesteric Liquid Crystal Fields

Molecules ◽

10.3390/molecules26196055 ◽

2021 ◽

Vol 26 (19) ◽

pp. 6055

Author(s):

Ju-Yong Kim ◽

Jae-Jin Lee ◽

Jun-Sung Park ◽

Yong-Jun Choi ◽

Suk-Won Choi

Keyword(s):

Liquid Crystal ◽

Crystal Field ◽

Driving Force ◽

Cholesteric Liquid Crystal ◽

Powerful Method ◽

Cholesteric Phase ◽

Crystal Fields

In this paper, a simple and powerful method to control the induced handedness of helical nanofilaments (HNFs) is presented. The nanofilaments are formed by achiral bent-core liquid crystal molecules employing a cholesteric liquid crystal field obtained by doping a rod-like nematogen with a chiral dopant. Homochiral helical nanofilaments are formed in the nanophase-separated helical nanofilament/cholesteric phase from a mixture with a cholesteric phase. This cholesteric phase forms at a temperature higher than the temperature at which the helical nanofilament in a bent-core molecule appears. Under such conditions, the cholesteric liquid crystal field acts as a driving force in the nucleation of HNFs, realizing a perfectly homochiral domain consisting of identical helical nanofilament handedness.

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Topology control of human fibroblast cells monolayer by liquid crystal elastomer

Science Advances ◽

10.1126/sciadv.aaz6485 ◽

2020 ◽

Vol 6 (20) ◽

pp. eaaz6485 ◽

Cited By ~ 11

Author(s):

Taras Turiv ◽

Jess Krieger ◽

Greta Babakhanova ◽

Hao Yu ◽

Sergij V. Shiyanovskii ◽

...

Keyword(s):

Liquid Crystal ◽

Orientational Order ◽

Topological Defects ◽

Density Fluctuations ◽

Dermal Fibroblasts ◽

Produce Cell ◽

Surface Anchoring ◽

Liquid Crystal Elastomer ◽

Anisotropic Surface ◽

Living Tissues

Eukaryotic cells in living tissues form dynamic patterns with spatially varying orientational order that affects important physiological processes such as apoptosis and cell migration. The challenge is how to impart a predesigned map of orientational order onto a growing tissue. Here, we demonstrate an approach to produce cell monolayers of human dermal fibroblasts with predesigned orientational patterns and topological defects using a photoaligned liquid crystal elastomer (LCE) that swells anisotropically in an aqueous medium. The patterns inscribed into the LCE are replicated by the tissue monolayer and cause a strong spatial variation of cells phenotype, their surface density, and number density fluctuations. Unbinding dynamics of defect pairs intrinsic to active matter is suppressed by anisotropic surface anchoring allowing the estimation of the elastic characteristics of the tissues. The demonstrated patterned LCE approach has potential to control the collective behavior of cells in living tissues, cell differentiation, and tissue morphogenesis.

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New liquid crystal formation induced by nanoscale phase separation composed of bent-core liquid crystal and rod-like cholesteric liquid crystal mixtures

Soft Matter ◽

10.1039/d0sm01748e ◽

2021 ◽

Author(s):

Yoichi Takanishi

Keyword(s):

Liquid Crystal ◽

Phase Separation ◽

Liquid Crystals ◽

Small Angle ◽

Cholesteric Liquid Crystal ◽

Crystal Formation ◽

Nano Structure ◽

X Ray ◽

Nanoscale Phase Separation ◽

X Ray Scattering

Herein, the local nano-structure in mixtures of cholesteric liquid crystals and a bent-core molecule was analyzed via the small-angle X-ray scattering.

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Fabrication of multicolored patterns based on dye-doped cholesteric liquid crystals

Photochemical & Photobiological Sciences ◽

10.1039/c9pp00150f ◽

2019 ◽

Vol 18 (7) ◽

pp. 1638-1648 ◽

Cited By ~ 2

Author(s):

Linlin Xu ◽

Hanbing Zhang ◽

Jie Wei

Keyword(s):

Liquid Crystal ◽

Liquid Crystals ◽

Fluorescence Enhancement ◽

Cholesteric Liquid Crystal ◽

Cholesteric Liquid Crystals ◽

Dual Mode

We developed a type of dye-doped cholesteric liquid crystal, which were used for fluorescence enhancement and dual-mode multicolor patterns.

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Supramolecular self-assembly and physical-gel formation in disc-like liquid crystals: a scalable predictive model for gelation and an application in photovoltaics

RSC Advances ◽

10.1039/c8ra09278h ◽

2019 ◽

Vol 9 (11) ◽

pp. 6335-6345

Author(s):

Sehrish Iqbal ◽

Ammar A. Khan

Keyword(s):

Liquid Crystal ◽

Liquid Crystals ◽

Predictive Model ◽

Self Assembly ◽

Gel Formation ◽

Discotic Liquid Crystal ◽

Physical Gel

The application of triphenylene-based discotic liquid crystal derivatives as physical gelators is investigated.

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Gold nanoparticle self-assembly moderated by a cholesteric liquid crystal

Soft Matter ◽

10.1039/c3sm51736e ◽

2013 ◽

Vol 9 (39) ◽

pp. 9366 ◽

Cited By ~ 31

Author(s):

Joel S. Pendery ◽

Olivier Merchiers ◽

Delphine Coursault ◽

Johan Grand ◽

Habib Ayeb ◽

...

Keyword(s):

Liquid Crystal ◽

Gold Nanoparticle ◽

Self Assembly ◽

Cholesteric Liquid Crystal

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Orientation, interaction and laser assisted self-assembly of organic single-crystal micro-sheets in a nematic liquid crystal

Soft Matter ◽

10.1039/c5sm01991e ◽

2015 ◽

Vol 11 (38) ◽

pp. 7674-7679 ◽

Cited By ~ 9

Author(s):

M. V. Rasna ◽

K. P. Zuhail ◽

U. V. Ramudu ◽

R. Chandrasekar ◽

J. Dontabhaktuni ◽

...

Keyword(s):

Experimental Study ◽

Liquid Crystal ◽

Liquid Crystals ◽

Single Crystal ◽

Nematic Liquid Crystal ◽

Self Assembly ◽

Nematic Liquid Crystals ◽

Directed Assembly ◽

Orientation Interaction ◽

Organic Single Crystal

In this paper we report first experimental study on the orientation, interaction and directed-assembly of single crystal micro-sheets in nematic liquid crystals.

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