Electric field‐induced birefringence, optical rotatory power and conoscopic measurements of a chiral antiferroelectric smectic liquid crystal

Manjuladevi, V.; Vij, J. K.

doi:10.1080/02678290701478103

Cited by 12 publications

(4 citation statements)

References 26 publications

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“…First, they undergo controllable, multistage field-induced transitions, with each phase exhibiting significantly different electrical and electro-optical properties despite their minute thermodynamic differences. 4,5 Second, despite significant theoretical and experimental work, 2,6 the origin of some of the phases not fully understood, and new, unexpected phases such as a six-layer phase, 7 continue to be revealed. This enhances both the richness of such materials with exciting properties and our understanding of these states of matter.…”

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confidence: 94%

A field-induced ferrielectric liquid crystal phase

Jaradat

Brimicombe

Osipov

et al. 2011

Applied Physics Letters

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Understanding the structures and stability conditions of emerging liquid crystal (LC) phases brings us a step closer to the crucial understanding of delicate self-assembling nanoscale systems and the consequential impact on their macroscopic properties. We report experimental evidence and a theoretical model for a ferrielectric LC phase which has a three-layer repeat structure and is field-induced but exhibits a symmetry and electro-optical properties that are distinct from those of the known ferrielectric (SmC�∗FI1) phase. This discovery has implications for the ways in which LC phases are identified, and offers the potential for better control of ferroelectric LC devices

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confidence: 94%

A field-induced ferrielectric liquid crystal phase

Jaradat

Brimicombe

Osipov

et al. 2011

Applied Physics Letters

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“…As a consequence, the electric field may induce specific organization of the supramolecular structure since the formation of dipoles and their arrangement facilitate better fitting of Congo red to conditions imposed by the external field (Gomes and Mallion 2001 ; Kimura 2008 ; Manjuladevi and Vij 2007 ; Schenning et al 2004 ). In the current work, the effect of the external electric field on the supramolecular organization of Congo red was verified by theoretical calculation.…”

Section: Resultsmentioning

confidence: 99%

Influence of the electric field on supramolecular structure and properties of amyloid-specific reagent Congo red

et al. 2011

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Among specific amyloid ligands, Congo red and its analogues are often considered potential therapeutic compounds. However, the results of the studies so far have not been univocal because the properties of this dye, derived mostly from its supramolecular nature, are still poorly understood. The supramolecular structure of Congo red, formed by π–π stacking of dye molecules, is susceptible to the influence of the electric field, which may significantly facilitate electron delocalization. Consequently, the electric field may generate altered physico-chemical properties of the dye. Enhanced electron delocalization, induced by the electric field, alters the total charge of Congo red, making the dye more acidic (negatively charged). This is a consequence of withdrawing electrons from polar substituents of aromatic rings—sulfonic and amino groups—thus increasing their tendency to dissociate protons. The electric field-induced charge alteration observed in electrophoresis depends on dye concentration. This concentration-dependent charge alteration effect disappears when the supramolecular structure disintegrates in DMSO. Dipoles formed from supramolecular fibrillar species in the electric field become ordered in the solution, introducing the modified arrangement to liquid crystalline phase. Experimental results and theoretical studies provide evidence confirming predictions that the supramolecular character of Congo red is the main reason for its specific properties and reactivity.

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“…The possible influence of an external electric field on the delocalization of π electrons may be direct or mediated by changes in the self-assembly dependent charge of dye substituents -amino and sulfonic groups [58][59][60][61][62][63]. For neutral or alkaline solutions, i.e., those with a pH above pK of the amino group, the negative charge of the sulfonate groups has a decisive influence on the charge of the dye.…”

Section: Dye-protein Complexation Conducted In An Applied External Elmentioning

confidence: 99%

Formation of amyloid-like aggregates through the attachment of protein molecules to a Congo red scaffolding framework ordered under the influence of an electric field

et al. 2010

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This study describes a technique which makes it possible to introduce the amyloid-like order to protein aggregates by using the scaffolding framework built from supramolecular, fibrillar Congo red structures arranged in an electric field. The electric field was used not only to obtain a uniform orientation of the charged dye fibrils, but also to make the fibrils long, compact and rigid due to the delocalization of pi electrons, which favors ring stacking and, as a consequence, results in an increased tendency to self-assemble. The protein molecules (immunoglobulin L chain lambda, ferritin) attached to this easily adsorbing dye framework assume its ordered structure. The complex precipitating as plate-like fragments shows birefringence in polarized light. The parallel organization of fibrils can be observed with an electron microscope. The dye framework may be removed via reduction with sodium dithionite, leaving the aggregated protein molecules in the ordered state, as confirmed by X-ray diffraction studies.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

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Electric field‐induced birefringence, optical rotatory power and conoscopic measurements of a chiral antiferroelectric smectic liquid crystal

Cited by 12 publications

References 26 publications

A field-induced ferrielectric liquid crystal phase

A field-induced ferrielectric liquid crystal phase

Influence of the electric field on supramolecular structure and properties of amyloid-specific reagent Congo red

Formation of amyloid-like aggregates through the attachment of protein molecules to a Congo red scaffolding framework ordered under the influence of an electric field

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