When a nematic liquid crystal is doped with a large amount of a liquid crystalline azobenzene compound (15 wt %), the photoisomerization of azobenzene under UV and visible light irradiation can give rise to reversible and interconvertible photochemical phase transition and photochemical phase separation. Both normal and reverse modes of photocontrolled switching of transmittance through crossed...

We report five ultra-low viscosity nematic liquid crystal mixtures with birefringence around 0.1, dielectric anisotropy in the range of 3 to 6, and clearing temperature about 80°C. A big advantage of these low viscosity mixtures is low activation energy, which significantly suppresses the rising rate of viscosity at low temperatures. Using our mixture M3 as an example, the response time of a 3-...

An analysis of and experimental demonstration of active optical tuning of silicon strip waveguides with methyl red doped nematic liquid crystal claddings is presented. Under low-power irradiation by polarized light, the reorientation of the nematic, the resulting index change, and phase shift produce a tuning range of 5.6 nm for the microresonator resonances.

The self-organizing properties of nematic liquid crystals can be used to align carbon nanotubes dispersed in them. Because the nanotubes are so much thinner than the elastic penetration length, the alignment is caused by the coupling of the unperturbed director field to the anisotropic interfacial tension of the nanotubes in the nematic host fluid. In order to relate the degree of alignment of ...

We consider free energy functionals to model equilibrium smectic A liquid crystal configurations in the neighborhood of the nematic phase transition. We begin with the functional proposed by de Gennes based on the Ginzburg–Landau model for superconductivity and consider its covariant formulations. Exploring qualitative analogies with the nonlinear elastic bar of Ericksen, we motivate a revision...

Nematic braids are reconfigurable knots and links formed by the disclination loops that entangle colloidal particles dispersed in a nematic liquid crystal. We focus on entangled nematic disclinations in thin twisted nematic layers stabilized by 2D arrays of colloidal particles that can be controlled with laser tweezers. We take the experimentally assembled structures and demonstrate the corresp...

The behavior of mono-disperse colloidal particles in a chromonic liquid crystal was investigated. Poly(methyl methacrylate) spherical particles with three different functionalizations, with and without surface charges, were utilized in the nematic and columnar phases of disodium cromoglycate solutions. The nematic phase was completely aligned parallel to the glass substrates by a simple rubbing...

We report a low-voltage and submillisecond-response polymerstabilized hyper-twisted-nematic (HTN) liquid crystal cell with a large dielectric anisotropy host mixture. To correct the measured voltagedependent transmittance, we have to take the voltage shielding effect of the alignment layers into consideration. Both Kerr effect and flexoelectro-optic effect contribute to the observed induced bir...

Liquid crystals exhibit orientation-dependent phases ranging from a disordered ~isotropic! phase to a highly ordered crystalline phase. In between these extremes, increasing order can result in nematic and smectic phases. Typically, molecular simulation studies of liquid-crystal behavior use a nonspherical hard-body monomer. In this work, molecular simulation is used to study dimers of hard pro...

The formation of optically isotropic liquid crystal (LC) media has been investigated by doping the star-shaped LC molecular surfactants (SiLC) into the rod-shaped twin LC host molecules (DiLC). The experimental phase diagram was constructed on the basis of differential scanning calorimetry (DSC) and then a theoretical calculation was conducted through a combined Flory-Huggins (FH)/Maier-Saupe-M...