Phase Transitions in Liquid Crystal Doped with Magnetic Particles of Different Shapes

Kopčanský, P.; Tomašovičová, Natália; Koneracká, M.; Τimko, M.; Závišová, V.; Džarová, A.; Jadżyn, Jan; Beaugnon, Eric; Chaud, X.

doi:10.1007/s10765-010-0781-1

Cited by 32 publications

(30 citation statements)

References 24 publications

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“…It has also been shown experimentally that the N-I transition temperature can be significantly affected by the presence of other types of NPs. For example, a decrease of the N-I transition temperature is observed in nematics doped with approximately isotropic silver, 21 gold 22 or aerosil particles, 23,24 while the N-I transition temperature increases if the nematic LC is doped with strongly anisotropic NPs including nanotubes, 25 magnetic nanorods 26 and ferroelectric particles.…”

Section: 15mentioning

confidence: 99%

Nematic liquid crystals doped with nanoparticles: Phase behavior and dielectric properties

Osipov

Gorkunov

2016

Series in Soft Condensed Matter

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Thermodynamics and dielectric properties of nematic liquid crystals doped with various nanoparticles have been studied in the framework of a molecular mean-field theory. It is shown that spherically isotropic nanoparticles effectively dilute the liquid crystal material and cause a decrease of the nematic-isotropic transition temperature, while anisotropic nanoparticles are aligned by the nematic host and, in turn, may significantly improve the liquid crystal alignment. In the case of strong interaction between spherical nanoparticles and mesogenic molecules, the nanocomposite possesses a number of unexpected properties: The nematic-isotropic co-existence region appears to be very broad, and the system either undergoes a direct transition from the isotropic phase into the phase-separated state, or undergoes first a transition into the homogeneous nematic phase and then phase-separates at a lower temperature. The phase separation does not occur for sufficiently low nanoparticle concentrations, and, in certain cases, the separation takes place only within a finite region of the nanoparticle concentration. For nematics doped with strongly polar nanoparticles, the theory predicts the nanoparticle aggregation in linear chains that make a substantial contribution to the static dielectric anisotropy and optical birefringence of the nematic composite. The theory clarifies the microscopic origin of important phenomena observed in nematic composites including a shift of the isotropic-nematic phase transition and improvement of the nematic order; a considerable softening of the first order nematic-isotropic transition; a complex phase-separation behavior; and a significant increase of the dielectric anisotropy and the birefringence. *

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Section: 15mentioning

confidence: 99%

Nematic liquid crystals doped with nanoparticles: Phase behavior and dielectric properties

Osipov

Gorkunov

2016

Series in Soft Condensed Matter

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“…В обоих случаях существуют определенные ограничения, относящиеся к размеру и форме НЧ. Как было показано в [13], сферическая форма НЧ приводит к уменьшению температуры перехода N-I (T N-I ), тогда как в нематиках с внедренными сильно анизотропными наночастицами T N-I увеличивается [14]. Эти эффекты объяснили с помощью теоретических исследований, которые привели к основным концепциям, касающихся НЧ, распределенных в анизотропной среде [21,23].…”

Section: фазовое разделение в композитах с нч помещенных в жк-системыunclassified

“…Другая группа самоорганизованных матриц для наночастиц представлена низкомолекуляр-ными жидкими кристаллами [10][11][12][13][14][15] и ЖК-поли-мерами [16][17][18][19][20]. Такие нанокомпозиты обладают новыми свойствами, отличающимися от свойств входящих в их состав жидких кристаллов и наночастиц.…”

Section: Introductionunclassified

Nanocomposites Based on Liquid Crystal Polymers and Inorganic Nanoparticles

Shatalova¹,

Shandryuk²,

Merekalov³

et al. 2015

Liq. Cryst. and their Appl.

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“…Indeed, the nematic-isotropic (N-I) phase transition temperature is decreased when the nematic liquid crystal is doped with isotropic silver [14], gold [15] or aerosil [16,17] NPs . At the same time, doping with strongly anisotropic NPs leads to an increase of the N-I transition temperature, which has been observed using nanotubes [18], magnetic nanorods (NRs) [19], and ferroelectric NPs [7,8]. Recently, the effect of NPs on the N-I phase transition and on the dielectric properties of nematic nano-composites has been described in terms of molecular statistical theory [20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Phase behavior and orientational ordering in block copolymers doped with anisotropic nanoparticles

et al. 2018

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This version is available at https://strathprints.strath.ac.uk/64399/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output.Phase behaviour and orientational ordering in block copolymers doped with anisotropic nanoparticles. A molecular field theory and coarse grained computer simulations with dissipative particle dynamics have been used to study the spontaneous orientational ordering of anisotropic nanoparticles in the lamellae and hexagonal phases of diblock copolymers and the effect of nanoparticles on the phase behaviour of these systems. Both a molecular theory and computer simulations indicate that strongly anisotropic nanoparticles are ordered orientationally mainly in the boundary region between the domains, and the nematic order parameter possesses opposite signs in adjacent domains. The orientational order is induced by the boundary and by the interaction between nanoparticles and the monomer units in different domains. In simulations, sufficiently long and strongly selective nanoparticles order also inside the domains. Nematic order parameter and local concentration profiles of nanoparticles have been calculated numerically using the model of a nanoparticle with two interaction centres and also determined using the results of computer simulations. A number of phase diagrams have been obtained which illustrate the effect of nanoparticle selectivity and molar fraction of the stability ranges of various phases. Different morphologies have been identified by analysing the static structure factor and a phase diagram has been constructed in coordinates nanoparticle concentration -copolymer composition. Orientational ordering of even a small fraction of nanoparticles may result in a significant increase of the dielectric anisotropy of a polymer nanocomposite which is important for various applications.

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Phase Transitions in Liquid Crystal Doped with Magnetic Particles of Different Shapes

Cited by 32 publications

References 24 publications

Nematic liquid crystals doped with nanoparticles: Phase behavior and dielectric properties

Nematic liquid crystals doped with nanoparticles: Phase behavior and dielectric properties

Nanocomposites Based on Liquid Crystal Polymers and Inorganic Nanoparticles

Phase behavior and orientational ordering in block copolymers doped with anisotropic nanoparticles

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