Computer simulations of biaxial nematics

Berardi, Roberto; Muccioli, Luca; Orlandi, Silvia; Ricci, Matteo; Zannoni, Claudio

doi:10.1088/0953-8984/20/46/463101

Cited by 120 publications

(112 citation statements)

References 174 publications

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“…The transition between biaxial and uniaxial * e-mail: andrzej.kapanowski@uj.edu.pl phases is usually second order, and a direct transition between isotropic and biaxial nematic phases is also predicted. Similar results were obtained from the analytical study of single-component systems consisting of biaxial molecules interacting via hard-core potentials [20][21][22][23][24][25], and confirmed by simulation results [26][27][28].…”

Section: Introductionsupporting

confidence: 85%

Statistical Theory of Biaxial Nematic and Cholesteric Phases

Kapanowski

2011

Acta Phys. Pol. A

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A statistical theory of biaxial nematic and cholesteric phases is presented. It is derived in the thermodynamic limit at small density and small distortions. The considered phases are composed of short rigid biaxial or less symmetric molecules. The expressions for various macroscopic parameters involve the one-particle distribution function and the potential energy of two-body short-range interactions. The cholesteric phase is regarded as a distorted form of the nematic phase. Exemplary calculations are shown for several systems of molecules interacting via Corner-type potential based on the Lennard-Jones 12-6 functional dependence. The temperature dependence of the order parameters, the elastic constants, the phase twists, the dielectric susceptibilities, and the flexoelectric coefficients are obtained. The flow properties and defects in nematics are also discussed.

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Section: Introductionsupporting

confidence: 85%

Statistical Theory of Biaxial Nematic and Cholesteric Phases

Kapanowski

2011

Acta Phys. Pol. A

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“…In the limit of uniaxial particles (χ = 0 • , 180 • and λ = 0) we recover mean-field results of Maier and Saupe. For ordinary biaxial molecules (χ = 0 • , 180 • and λ = 0) the model becomes reduced to mean-field version of the well known Lebwohl-Lasher dispersion model 39,50 . As all bent-core molecules are biaxial 51 our generalization seems important for it allows to control intrinsic molecular biaxiality (by two molecular features: bend angle and arm anisotropy).…”

Section: Discussionmentioning

confidence: 99%

Twist-bend nematic phases of bent-shaped biaxial molecules

2016

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How change in molecular structure can affect relative stability and structural properties of the twist-bend nematic phase (N TB )? Here we extend the mean-field model 1 for bent-shaped achiral molecules, to study the influence of arm molecular biaxiality and the value of molecule's bend angle on relative stability of N TB . In particular we show that by controlling biaxiality of molecule's arms up to four ordered phases can become stable. They involve locally uniaxial and biaxial variants of N TB , together with the uniaxial and the biaxial nematic phases. However, the Vshaped molecule show stronger ability to form stable N TB than a biaxial nematic phase, where the latter phase appears in the phase diagram only for bend angles greater than 140 • and for large biaxiality of the two arms.

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“…The characteristic feature of the biaxial phase is that two directions of orientational ordering occur associated with two molecular symmetry axes [2]. The importance of studying biaxial nematic phases is that they might be used in practical applications, such as fast electro-optical devices [3].…”

Section: Introductionmentioning

confidence: 99%

Effect of shape biaxiality on the phase behavior of colloidal liquid-crystal monolayers

Gonzalez-Pinto

Martı́nez-Ratón

Velasco

et al. 2015

Phys. Chem. Chem. Phys.

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We extend our previous work on monolayers of uniaxial particles [J. Chem. Phys. 140, 204906 (2014)] to study the effect of particle biaxiality on the phase behavior of liquid-crystal monolayers.Particles are modelled as board-like hard bodies with three different edge lengths σ 1 ≥ σ 2 ≥ σ 3 , and use is made of the restricted-orientation approximation (Zwanzig model). A density-functional formalism based on the fundamental-measure theory is used to calculate phase diagrams for a wide range of values of the largest aspect ratio (κ 1 = σ 1 /σ 3 ∈ [1, 100]). We find that particle biaxiality in general destabilizes the biaxial nematic phase already present in monolayers of uniaxial particles.While plate-like particles exhibit strong biaxial ordering, rod-like ones with κ 1 > 21.34 exhibit reentrant uniaxial and biaxial phases. As particle geometry is changed from uniaxial-to increasingly biaxial-rod-like, the region of biaxiality is reduced, eventually ending in a critical-end point. For κ 1 > 60, a density gap opens up in which the biaxial nematic phase is stable for any particle biaxiality. Regions of the phase diagram where packing-fraction inversion occurs (i.e. packing fraction is a decreasing function of density) are found. Our results are compared with the recent experimental studies on nematic phases of magnetic nanorods.

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Computer simulations of biaxial nematics

Cited by 120 publications

References 174 publications

Statistical Theory of Biaxial Nematic and Cholesteric Phases

Statistical Theory of Biaxial Nematic and Cholesteric Phases

Twist-bend nematic phases of bent-shaped biaxial molecules

Effect of shape biaxiality on the phase behavior of colloidal liquid-crystal monolayers

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