Template‐Guided Organization of Chromonic Liquid Crystals into Micropatterned Anisotropic Organic Solids.

Tam-Chang, Suk-Wah; Helbley, Jennifer; Carson, Travis D.; Seo, Wonewoo; Iverson, Isaac K.

doi:10.1002/chin.200620219

Cited by 3 publications

(5 citation statements)

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“…1−4 LCLC phases are typically observed in dyes, 7−10 drugs, 11,12 and nucleic acids. 13,14 Moreover, chromonics have shown a growing number of potential applications, such as biosensing, 15,16 development of organic electronics, 17 micropatter-ing, 18,19 preparation of highly ordered dried films, 20 fabrication of vertically aligned graphene layers, 21 and active matter manipulation. 22 The aggregation model of CMs could also be useful for expanding the understanding of the spontaneous aggregation of aromatic compounds decorated with polar substituents in solution.…”

Section: ■ Introductionmentioning

confidence: 99%

Effects of Sodium and Magnesium Cations on the Aggregation of Chromonic Solutions Using Molecular Dynamics

Rivas

Rey

2019

J. Phys. Chem. B

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Lyotropic chromonic liquid crystals (LCLCs) constitute a unique variety of water-soluble mesogens that spontaneously assemble into elongated aggregates, thereby resulting in the formation of liquid crystal phases depending on the temperature and concentration. The influence of ionic additives on the aggregation of LCLC has been extensively studied, but the molecular mechanisms governing these effects remain unclear. In this investigation, we perform atomistic molecular dynamics simulations of dilute sunset yellow (SSY) LCLC solutions doped with NaCl and MgCl2 salts. Structural and dynamical properties of SSY hydration shells are considerably modified by the partial substitution of their H bonds with sodium/magnesium-sulfonate ion pairs. Although the intermolecular distance of ∼3.4 Å between SSY mesogens is preserved regardless of the ionic content, the growing number of ion pairs favors the reduction of the electrostatic repulsion between mesogens, increasing the length of SSY stacks. Moreover, magnesium cations exert the strongest electrostatic effects due to their higher hydration capabilities and acute electrostatic binding to SSY. For these reasons, experimental observations of dilute SSY solutions doped with Mg2+ exhibit higher nematic-to-isotropic transition temperatures than Na+. This work provides a fundamental understanding of the influence of ionic additives on the self-assembly of diluted LCLC solutions derived from the synergistic molecular mechanisms between mesogens, the solvent, and cations.

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Section: ■ Introductionmentioning

confidence: 99%

Effects of Sodium and Magnesium Cations on the Aggregation of Chromonic Solutions Using Molecular Dynamics

Rivas

Rey

2019

J. Phys. Chem. B

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“…LCLCs show a potential for new applications, such as controlled drug delivery [1], biosensing [10], preparation of optically anisotropic films [11], micro-patterning [12], nano-fabrication [13], etc.…”

Section: Introductionmentioning

confidence: 99%

“…The aggregates’ length depends not only on the concentration but also on the specific details of molecular interactions, temperature, ,, ionic content, − pH of the solution, and type of the side groups. , The LCLCs thus represent an interesting self-assembled system with an orientational and positional order that is highly sensitive to a number of factors. The chromonic family should be extended to include the DNA nucleotides, such as guanosine derivatives. , LCLCs show a potential for new applications, such as controlled drug delivery, biosensing, preparation of optically anisotropic films, micropatterning, nanofabrication, and so forth.…”

Section: Introductionmentioning

confidence: 99%

Condensation of Self-Assembled Lyotropic Chromonic Liquid Crystal Sunset Yellow in Aqueous Solutions Crowded with Polyethylene Glycol and Doped with Salt

et al. 2011

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We use optical and fluorescence microscopy, densitometry, cryo-transmission electron microscopy (cryo-TEM), spectroscopy, and synchrotron X-ray scattering to study the phase behavior of the reversible self-assembled chromonic aggregates of an anionic dye Sunset Yellow (SSY) in aqueous solutions crowded with an electrically neutral polymer polyethylene glycol (PEG) and doped with the salt NaCl. PEG causes the isotropic SSY solutions to condense into a liquid-crystalline region with a high concentration of SSY aggregates, coexisting with a PEG-rich isotropic (I) region. PEG added to the homogeneous nematic (N) phase causes separation into the coexisting N and I domains; the SSY concentration in the N domains is higher than the original concentration of PEG-free N phase. Finally, addition of PEG to the highly concentrated homogeneous N phase causes separation into the coexisting columnar hexagonal (C) phase and I phase. This behavior can be qualitatively explained by the depletion (excluded volume) effects that act at two different levels: at the level of aggregate assembly from monomers and short aggregates and at the level of interaggregate packing. We also show a strong effect of a monovalent salt NaCl on phase diagrams that is different for high and low concentrations of SSY. Upon the addition of salt, dilute I solutions of SSY show appearance of the condensed N domains, but the highly concentrated C phase transforms into a coexisting I and N domains. We suggest that the salt-induced screening of electric charges at the surface of chromonic aggregates leads to two different effects: (a) increase of the scission energy and the contour length of aggregates and (b) decrease of the persistence length of SSY aggregates.

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“…Stacking Distance Analysis. The actual separation between stacked chromone planes, d S = nî • d i, j , is computed as the scalar projection of vector d i, j , defined between the center of mass of adjacent chromone rings i, j onto n̂i, which is the unit normal vector to the chromone plane i. n̂i is in turn obtained from the cross product of two vectors formed between carbon pairs (16,6) and (14,10) (see Figure S1, Supporting Information) or their equivalent pairs from mirror chromone ring. Stacked chromone planes i, j were identified utilizing the aggregate/atom compute in LAMMPS with a cutoff distance of 5.4 Å.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The range of materials that exhibit chromonic aggregation includes dyes, 6−8 drugs, 9,10 and nucleic acids. 11,12 Some of the emerging technological applications of LCLCs include the development of biosensors, 13,14 production of highly ordered dried films, 15 micropatterning, 16,17 active matter manipulation, 18 pharmacological activity, 9 and the fabrication of vertically aligned graphene arrays. 19 Also, the aggregation model of chromonics could contribute to expanding the understanding of the supramolecular aggregation of organic materials in solution, such as mixtures of CMs and B-DNA bases, 20 biological liquid crystals, 21,22 and collagen films.…”

Section: ■ Introductionmentioning

confidence: 99%

Molecular Dynamics Study of the Effect of l-Alanine Chiral Dopants on Diluted Chromonic Solutions

Rivas

Rey

2019

J. Phys. Chem. B

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Atomistic molecular dynamics simulations have been performed for disodium cromoglycate (DSCG) chromonic solutions mixed with l-alanine chiral dopants. We study the fundamental molecular mechanisms induced by low concentrations of l-alanine on diluted DSCG solutions, including their effect on the chromonic aggregates, the solvent, and sodium counterions. Simulations reveal that l-alanine molecules primarily interact with DSCG stacks establishing salt bridges between their respective ammonium and carboxylate groups. Our results demonstrate that l-alanine and sodium counterions jointly establish an intricate network of noncovalent interactions around DSCG aggregates that decreases the global electrostatic repulsion of the chromonic system. Two possible structural effects in DSCG aggregates arise from this electronic stabilization: the increment of the total number of consecutively stacked aromatic planes per DSCG aggregate (intracolumnar effect) or the partial separation reduction between neighboring DSCG columnar sections due to the simultaneous bridging of intercolumnar DSCG carboxylate sites by sodium counterions, forming sodium bridges (intercolumnar effect). Sodium bridges may be responsible for the formation of stacking faults in DSCG aggregates in the form of lateral overlap junctions. This mechanism would explain the difference between lower X-ray correlation lengths with the expected persistence length in chromonics.

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Template‐Guided Organization of Chromonic Liquid Crystals into Micropatterned Anisotropic Organic Solids.

Abstract: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Cited by 3 publications

References 1 publication

Effects of Sodium and Magnesium Cations on the Aggregation of Chromonic Solutions Using Molecular Dynamics

Effects of Sodium and Magnesium Cations on the Aggregation of Chromonic Solutions Using Molecular Dynamics

Condensation of Self-Assembled Lyotropic Chromonic Liquid Crystal Sunset Yellow in Aqueous Solutions Crowded with Polyethylene Glycol and Doped with Salt

Molecular Dynamics Study of the Effect of l-Alanine Chiral Dopants on Diluted Chromonic Solutions

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