abstractthe liquid crystal director distribution is determined for a confined chiral nematic slab. the molecular director distribution of the field-controlled chiral nematic slab is directly calculated. the director profiles for the tilt and the twist angles, under different applied fields, are calculated in the slab with weak boundary conditions. then, the dependence of the threshold field on ...

Predicting the macroscopic chiral behaviour of liquid crystals from the microscopic chirality of the particles is highly non-trivial, even when the chiral interactions are purely entropic in nature. Here we introduce a novel chiral hard-particle model, namely particles with a twisted polyhedral shape and obtain a stable fully entropy-driven cholesteric phase by computer simulations. By slightly...

This paper describes a Monte Carlo simulation technique designed to predict the sign and magnitude of the helical twisting power, bM, of a chiral material. The method calculates the chemical potential difference, Dm, between a chiral dopant and its enantiomer when they are placed in a twisted nematic solvent. In the low concentration limit, Dm is directly proportional to bM. In the simulations ...

We have studied chiral induction in a nematic in contact with a chiral surface using computer simulations. Nematic and surface particles have been modelled using the GayÈBerne (GB) potential considering, additionally, a short-range chiral term for the inducing surface. We Ðnd that, close to the chiral surface, a twist of the local director with respect to the surface molecules is induced, even ...

The helical twisting power determines the pitch of the helical structure produced by introducing a given concentration of chiral dopant molecules to a nematic liquid crystal phase. By using novel, twisted, periodic boundary conditions, and measuring the relative chemical potentials of right-and left-handed dopants in a twisted nematic phase, we have succeeded in measuring this property by compu...

In many colloidal systems, an orientationally ordered nematic (N) phase emerges from the isotropic (I) melt in the form of spindle-like birefringent tactoids. In cases studied so far, the tactoids always reveal a mirror-symmetric nonchiral structure, sometimes even when the building units are chiral. We report on chiral symmetry breaking in the nematic tactoids formed in molecularly nonchiral p...

We stabilize nematic droplets with handles against surface tension-driven instabilities, using a yield-stress material as outer fluid, and study the complex nematic textures and defect structures that result from the competition between topological constraints and the elasticity of the nematic liquid crystal. We uncover a surprisingly persistent twisted configuration of the nematic director ins...

A high-resolution ac calorimetric study has been carried out on two homologous polar liquid crystals with aromatic cores containing three phenyl groups and a flexible chiral linking group. The expected smectic polymorphism occurs, and there are several prominent thermal features in the nematic range between smecticAd and smectic-C̃ phases. It is suggested on the basis of characteristic thermal s...

We demonstrate a simple method for measuring the twist elastic constant (K22) of a nematic liquid crystal (LC). By adding some chiral dopant to an LC host, the LC directors rotate 180° in a homogeneous cell, which is known as 180° super-twisted nematic (STN) cell. By preparing two such STN cells with different chiral concentrations and measuring their Fréedericksz threshold voltages, we can obt...

The defect structures of s = ±1/2 twist disclinations in twisted nematic and twisted chiral liquid crystals have been investigated within the Landau-de Gennes theory numerically. Our results show that there exists eigenvalue exchange across the defect core of both the two models. The defect core is essentially biaxial and never isotropic. The defect centre is uniaxial and is surrounded by a str...