We report experimental studies on 2D colloidal crystals of dimers stabilized by vortex-like defects in planar nematic and π/2 twisted nematic cells. The dimers are prepared and self-assembled using a laser tweezer. We study the effect of temperature and electric field on the lattice parameters of the colloidal crystals. The lattice parameters vary with the temperature in the nematic phase and a...

Mesogenic chiral esters of optically active (S)-l,2-propanediol and (R,R)-2,3-butanediol were synthesized. The compounds, added to a nematic phase induce cholesteric phases exhibiting a helix inversion with temperature variation. This effect is independent of the molecular structure of the nematic solvent. The inversion temperature varies only slightly with concentration but can be influenced b...

In this paper we demonstrate photonic band-edge laser emission from emulsion-based polymer dispersed liquid crystals. The lasing medium consists of dye-doped chiral nematic droplets dispersed within a polymer matrix that spontaneously align as the film dries. Such lasers can be easily formed on single substrates with no alignment layers. The system combines the self-organizing periodic structur...

We construct phase diagrams for charged rodlike colloids within the second-virial approximation as a function of rod concentration, salt concentration, and colloidal charge. Besides the expected isotropic-nematic transition, we also find parameter regimes with a coexistence between a nematic and a second, more highly aligned nematic phase including an isotropic-nematic-nematic triple point and ...

2014 Based on the Oseen and Frank elastic continuum theory of nematic liquid crystals and on a generalized torque balance equation at the liquid crystal-to-substrate interface, static deformations of a semi-infinite liquid crystal (LC) medium, a homogeneous LC cell, and a twisted nematic cell have been investigated using the anisotropic LC-to-substrate anchoring energy C as a parameter. Storage...

The temperature dependence of the rotational viscosities of several physically markedly different binary mixtures belonging to ten different liquid crystal classes is measured. An attempt is made to correlate the results with class-specific structural properties such as hydrogenated rings, molecular polarity and structure of flexible side-chains. It is show that the measured smallscale dynamic ...

2014 A study has been made of the use of optically active additives in twisted nematic devices to remove areas of reverse twist, the results obtained depending on the chirality of the additives and the director alignment on the two containing surfaces. Under certain conditions degeneracy of the field induced reorientation of the director produces a patched appearance even in the absence of reve...

Permanent grayscales in a π bistable twisted nematic liquid crystal display have been demonstrated. This display can be switched between –22.5° and 157.5° twist states by means of a combination of strong in-plane electric fields and vertical electric field for creating both the planar anchoring breaking and an electrohydrodynamic flow. The switching of the twist states during the Frederiks tran...