We have constructed polymer-stabilized nematic liquid crystals by photopolymerizing diacrylate monomers in the nematic phase. The orientation of the liquid crystal was controlled by the polymer network. We studied the Freedericksz transition in these systems. Experimentally we studied the transition by measuring the capacitance of the liquid crystal cells as a function of applied voltage. The t...

The nematic liquid crystal phase is a phase of matter in which the particles have a preferred orientational direction, as opposed to the liquid phase, with no preferred direction, and the solid crystal phase, with an ordered lattice structure. In an aggregated dye, or chromonic, liquid crystal, molecules aggregate together, and the aggregates form a liquid crystal. Aggregated dyes that form liq...

The electrically tunable properties of liquid-crystal fishnet metamaterials are theoretically investigated in the terahertz spectrum. A nematic liquid crystal layer is introduced between two fishnet metallic structures, forming a voltage-controlled metamaterial cavity. Tuning of the nematic molecular orientation is shown to shift the magnetic resonance frequency of the metamaterial and its over...

We study the phase behavior of a nematic liquid crystal confined between a flat substrate with strong anchoring and a patterned substrate whose structure and local anchoring strength we vary. By first evaluating an effective surface free-energy function characterizing the patterned substrate, we derive an expression for the effective free energy of the confined nematic liquid crystal. Then we d...

We investigate the azimuthal dependence of the switching field strength for nematic liquid crystal bistability on patterned alignment layers to determine the validity of a switching theory proposed by Kim et al. [Appl. Phys. Lett. 78, 3055 (2001)] and to evaluate higher-order azimuthal anchoring coefficients. Director behavior during switching is described in detail for general azimuthal direct...

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Electro-Optic Response of Liquid Crystals . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The Liquid Crystalline State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Physical Properties of Liquid Crystals . . . . . . . . . . . . . . . . . . . . . . ....

The synthesis and characterization of triynylbenzenes, 1-iodo-2,4,5-tri(4-alkoxyphenylethynyl)benzenes (1), are reported, and their structure–mesomorphism relationship is investigated. These compounds possess a y-shaped geometry with rigid linear spacers and a stable nematic phase that was achieved by lengthening the alkoxy chains or replacing the iodo group with a smaller atom. The low aspect ...

We demonstrate subnanometer resolution cryo-TEM imaging of smectic layers in the smectic and nematic phases of two bent-core liquid crystals. Our results show perfect periodicity over several hundred layers in the smectic phase and also provide the first direct evidence of smectic clusters on length scales of 30-50 nm in a nematic liquid crystal. The results are corroborated with small angle x-...