Lyotropic Chromonic Liquid Crystals: Emerging Applications

Park, Heung‐Shik; Lavrentovich, Oleg D.

doi:10.1002/9781118259993.ch14

Cited by 57 publications

(74 citation statements)

References 107 publications

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“…When salts are added, at a given temperature, the effect of NaCl and MgSO 4 is different, namely, NaCl leads to a smaller 3 K and MgSO 4 makes 3 K larger. In presence of even small amount of NaOH (0.01mol/kg), 3 K decreases. The bend constant is determined first of all by the flexibility of the aggregates that can be described by the persistence length p  , defined as the length over which unit vectors tangential to the aggregates lose correlation.…”

Section: Resultsmentioning

confidence: 98%

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Ionic-Content Dependence of Viscoelasticity of the Lyotropic Chromonic Liquid Crystal Sunset Yellow

Zhou

2017

Springer Theses

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3 Self-assembly of organic molecules in water is central to functioning of biological systems and to a broadening range of modern technologies utilizing soft matter. The mechanisms driving a diverse spectrum of self-organized structures are complex and involve a delicate balance of dispersive, hydrophobic/hydrophilic, depletion, and electrostatic forces. To understand these mechanisms, it is important to design model systems in which the structural and mechanical features can be experimentally measured in a reliable way and connected to the underlying composition. In this work, we explore the so-called lyotropic chromonic liquid crystals (LCLCs) as such a system that allows one to deduce the effect of ionic content on viscoelastic properties of orientationally ordered assemblies of organic molecules in aqueous solutions.LCLCs represent a broad class of materials formed in water dispersions of planklike or disk-like polyaromatic molecules with ionizable groups at the periphery, Fig. 1A.Face-to-face attraction of molecules forms elongated aggregates, Fig. 1B Material and Methods LCLC SSY with ionic additives.The disodium salt of 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonic acid, a widely used food dye generally known as sunset yellow (SSY) was purchased from Sigma-Aldrich (90% purity) and purified twice following previously established procedures [13,19,20]. Deionized water (resistance > 18.1 MΩ cm  ) was used to make the original SSY c =0.98mol/kg solution. The mixing was done on a vortex mixer at 2000rpm in isotropic phase for several minutes, then room temperature overnight. The SSY mixture was then split into smaller portions to add salts NaCl The =0.98mol/kg + NaOH solutions were made following previously reported procedure [13] by adding SSY into NaOH (Reagent, Acros) solutions of 0.01 and 0.02mol/kg and then mixing in vortex for 3hrs. Plastic vials and pipets were used to avoid reaction between NaOH and glass that reduces pH and affects LCLC properties. Viscoelastic constants measurement. We follow the customized magnetic Frederikstransition technique for LCLCs, using cells of two distinct surface alignments, planar and homeotropic anchoring, to measureanisotropy. In the twist measurement setup, we measure the dynamics of optical response to abruptly changed magnetic field and obtain the rotation viscosity coefficient 1(see Appendix C).   is measured using a superconducting quantum interference device (SQUID) following Ref [18,22] (results will be reported elsewhere). Results and DiscussionThe aqueous solution of SSY is probably the simplest LCLC in terms of ConclusionWe measured the temperature and ionic content dependences of anisotropic elastic moduli and rotation viscosity of the self-assembled orientationally ordered system formed by the polydisperse self-assembled aggregates of dye SSY bound by weak non-covalent forces. We observe dramatic and versatile changes of the viscoelastic properties induced by the ionic additives that alter the electrostatic interactions caused by charged gro...

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Section: Resultsmentioning

confidence: 98%

“…1B. Once the concentration of organic component exceeds some critical level, the aggregates align parallel to each other, producing a uniaxial nematic phase [1][2][3][4][5][6]. When the concentration is further increased, the aggregates pack into a two dimensional hexagonal lattice and form a columnar phase [1].…”

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confidence: 99%

Ionic-Content Dependence of Viscoelasticity of the Lyotropic Chromonic Liquid Crystal Sunset Yellow

Zhou

2017

Springer Theses

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“…Another limitations is that the review focuses on thermotropic LCs and does not discuss much their lyotropic counterparts [201][202][203] . Some of the presented features and mechanisms should be relevant to both types of LCs.…”

Section: Discussionmentioning

confidence: 99%

Transport of particles in liquid crystals

2014

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“…Droplets of thermotropic liquid crystals (TLCs) and the manipulation of their director configurations, for example, are actively studied, in part because of their demonstrated use as core materials in display technologies (3, 13) and their potential applications ranging from biosensors (14, 15) to microlasers (16). Indeed, significant fundamental and technological progress has been made with TLC droplets, because their bulk elasticity and surface anchoring phenomena are now well understood and easily controlled.Lyotropic chromonic liquid crystals (LCLCs) are composed of organic, charged, and plank-like mesogens that self-assemble in water into columnar aggregates via noncovalent electrostatic, excluded volume, hydrophobic, and pi-pi stacking interactions (17)(18)(19)(20). The aggregates, in turn, assemble into nematic or columnar phases, depending on temperature and concentration.…”

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confidence: 99%

“…Lyotropic chromonic liquid crystals (LCLCs) are composed of organic, charged, and plank-like mesogens that self-assemble in water into columnar aggregates via noncovalent electrostatic, excluded volume, hydrophobic, and pi-pi stacking interactions (17)(18)(19)(20). The aggregates, in turn, assemble into nematic or columnar phases, depending on temperature and concentration.…”

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Chiral symmetry breaking and surface faceting in chromonic liquid crystal droplets with giant elastic anisotropy

Jeong

Davidson

Collings

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

127

133

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Confined liquid crystals (LC) provide a unique platform for technological applications and for the study of LC properties, such as bulk elasticity, surface anchoring, and topological defects. In this work, lyotropic chromonic liquid crystals (LCLCs) are confined in spherical droplets, and their director configurations are investigated as a function of mesogen concentration using bright-field and polarized optical microscopy. Because of the unusually small twist elastic modulus of the nematic phase of LCLCs, droplets of this phase exhibit a twisted bipolar configuration with remarkably large chiral symmetry breaking. Further, the hexagonal ordering of columns and the resultant strong suppression of twist and splay but not bend deformation in the columnar phase, cause droplets of this phase to adopt a concentric director configuration around a central bend disclination line and, at sufficiently high mesogen concentration, to exhibit surface faceting. Observations of director configurations are consistent with Jones matrix calculations and are understood theoretically to be a result of the giant elastic anisotropy of LCLCs.emulsions | complex colloids T he director configurations of confined liquid crystals exhibit a rich phenomenology, the physics of which is determined by a delicate interplay of topology, elastic free energy, and anchoring conditions at the boundaries (1-12). Droplets present arguably the simplest and most symmetric confining container for liquid crystals. Droplets of thermotropic liquid crystals (TLCs) and the manipulation of their director configurations, for example, are actively studied, in part because of their demonstrated use as core materials in display technologies (3, 13) and their potential applications ranging from biosensors (14, 15) to microlasers (16). Indeed, significant fundamental and technological progress has been made with TLC droplets, because their bulk elasticity and surface anchoring phenomena are now well understood and easily controlled.Lyotropic chromonic liquid crystals (LCLCs) are composed of organic, charged, and plank-like mesogens that self-assemble in water into columnar aggregates via noncovalent electrostatic, excluded volume, hydrophobic, and pi-pi stacking interactions (17)(18)(19)(20). The aggregates, in turn, assemble into nematic or columnar phases, depending on temperature and concentration. A variety of organic molecules such as dyes, drugs, and biomolecules form LCLCs (17-28). However, far less is known about the fundamental science and applications potential of LCLCs than the more-studied TLCs. Indeed, basic properties of LCLCs, including aggregate size distribution and formation dynamics, bulk elasticity, and surface anchoring are neither fully characterized nor understood and are the subject of exciting ongoing research. Only recently, for example, have measurements been made of fundamental properties, such as the FrankOseen elastic constants (28, 29), of any LCLC, and they have revealed unusual concentration and temperature dependences of the splay ...

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Lyotropic Chromonic Liquid Crystals: Emerging Applications

Cited by 57 publications

References 107 publications

Ionic-Content Dependence of Viscoelasticity of the Lyotropic Chromonic Liquid Crystal Sunset Yellow

Ionic-Content Dependence of Viscoelasticity of the Lyotropic Chromonic Liquid Crystal Sunset Yellow

Transport of particles in liquid crystals

Chiral symmetry breaking and surface faceting in chromonic liquid crystal droplets with giant elastic anisotropy

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