Orientation of a solid particle embedded in a monodomain nematic liquid crystal

Бурылов, С. В.; Raǐkher, Yu. L.

doi:10.1103/physreve.50.358

Cited by 157 publications

(133 citation statements)

References 11 publications

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“…A similar effect has been demonstrated for pure liquid crystals [34,35], and also is well-known in the field of ferronematics [36]. X-ray diffraction of such a system is not reported due to the continuing problem of poor contrast between the two species and only low nanotube concentrations studied.…”

Section: Induced Orientation Of Nanotubesmentioning

confidence: 62%

Infrared actuation in aligned polymer-nanotube composites

et al. 2006

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Rubber composites containing multi-walled carbon nanotubes have been irradiated with near infrared light to study their reversible photo-mechanical actuation response. We demonstrate that the actuation is reproducible across differing polymer systems. The response is directly related to the degree of uniaxial alignment of the nanotubes in the matrix, contracting the samples along the alignment axis. The actuation stroke depends on the specific polymer being tested, however, the general response is universal for all composites tested. We conduct a detailed study of tube alignment induced by stress and propose a model for the reversible actuation behavior, based on the orientational averaging of the local response. The single phenomenological parameter of this model describes the response of an individual tube to adsorption of low-energy photons; its experimentally determined value may suggest some ideas about such a response.

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Section: Induced Orientation Of Nanotubesmentioning

confidence: 62%

Infrared actuation in aligned polymer-nanotube composites

et al. 2006

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“…Results presented in Fig. 6 indicate that the dependence of the torque on the rod tilt angle is far from the sin 2θ, proposed in [22]. Moreover, the torque is not equal to zero for θ = 0 0 , i.e.…”

Section: B Torque On the Particlementioning

confidence: 68%

“…The answer to the second question is not known even in the framework of phenomenological (continuum) theory [22]. The results of the theory only indicate that, depending on the type and strength of anchoring, the equilibrium position of the particle may be either parallel or perpendicular to the liquid crystal director.…”

Section: Introductionmentioning

confidence: 99%

Defect structures and torque on an elongated colloidal particle immersed in a liquid crystal host

et al. 2002

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Combining molecular dynamics and Monte Carlo simulation we study defect structures around an elongated colloidal particle embedded in a nematic liquid crystal host. By studying nematic ordering near the particle and the disclination core region we are able to examine the defect core structure and the difference between two simulation techniques. In addition, we also study the torque on a particle tilted with respect to the director, and modification of this torque when the particle is close to the cell wall.

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“…The formulas (38) and (42) provide a mathematical basis for classifying all the possible types of dipolar colloids. Thus, in general, an elastic dipole can be described by the three coefficients d, ∆, C, and the vector d 3 : the isotropic dipole strength, anisotropy, chirality, and the longitudinal component.…”

Section: -15mentioning

confidence: 99%

Colloidal nematostatics

Pergamenshchik¹,

Uzunova²

2010

Condens. Matter Phys.

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We give a review of the theory of large distance colloidal interaction via the nematic director field. The new area of nematic colloidal systems (or nematic emulsions) has been guided by the analogy between the colloidal nematostatics and electrostatics. The elastic charge density representation of the colloidal nematostatics [V.M. Pergamenshchik, V.O. Uzunova, Eur. Phys. J. E, 2007, 23, 161; Phys. Rev. E, 2007, 76, 011707] develops this analogy at the level of charge density and Coulomb interaction. The analogy is shown to lie in common mathematics based on the solutions of Laplace equation. However, the 3d colloidal nematostatics substantially differs from electrostatics both in its mathematical structure and physical implications. The elastic charge is a vector fully determined by the torque exerted upon colloid, the role of Gauss' theorem is played by conservation of the torque components. Elastic multipoles consist of two tensors (dyads). Formulas for the elastic multipoles, the Coulomb-like, dipole-dipole, and quadrupole-quadrupole pair interaction potentials are derived and illustrated by particular examples. Based on the tensorial structure, we list possible types of elastic dipoles and quadrupoles. An elastic dipole is characterized by its isotropic strength, anisotropy, chirality, and its longitudinal component. An elastic quadrupole can be uniaxial and biaxial. Relation between the multipole type and its symmetry is discussed, sketches of some types of multipoles are given. Using the mirror image method of electrostatics as a guiding idea, we develop the mirror image method in nematostatics for arbitrary director tilt at the wall. The method is applied to the charge-wall and dipole-wall interaction. : 61.30.Dk, 61.30.Jf, 82.70Dd, 01.55.+b 1. The intrigue of nematic colloids: similarity to the electrostatics, its origin, and how it is developed in this article. Key words: nematic colloid, electrostatic analogy, elastic charge and multipoles PACSIsotropic liquids doped with colloidal particles or just colloids are the classical many-particle systems which, over many decades , have been studied using the methods of molecular and statistical physics, electrolyte theory, physical chemistry, and so on [1,2]. Colloidal particles can be of different physical and chemical origin, but in all cases their interaction via isotropic liquid is of a short range [3], even if the colloids are charged since their electric field is rapidly screened by a numerous couterions. The nematic colloids, that have become widely known just over the last 15 years, are fundamentally different: interaction of colloids mediated by distortions of the nematic director is of a long range. That is why nematic colloids are usually compared not with standard isotropic colloids, but with a system of electric charges. The similarity with the electrostatics has always been a powerful, if not dominating, factor of the development of the field of nematic colloids. But what is the origin of this similarity?The interaction of particles in a ne...

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Orientation of a solid particle embedded in a monodomain nematic liquid crystal

Cited by 157 publications

References 11 publications

Infrared actuation in aligned polymer-nanotube composites

Infrared actuation in aligned polymer-nanotube composites

Defect structures and torque on an elongated colloidal particle immersed in a liquid crystal host

Colloidal nematostatics

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