Phase behaviors of colloidal analogs of bent-core liquid crystals.

Bent-core liquid crystal (LC) molecules are known to form mesophases with fascinating polar order and supramolecular chirality despite the achiral nature of the mesogens. The assembly of colloidal particles with geometrical similarity to bent-core molecular mesogens not only provides new insights into the physical behaviors of atoms or molecules but also leads to new materials with broad applications. Despite tremendous progress in colloidal synthesis and assembly, there has been a lack of colloidal model systems of bent-core molecular mesogens for LC property discovery and application development.

Synthesis and Liquid-Crystal Behavior of Bent Colloidal Silica Rods.

The design and assembly of novel colloidal particles are of both academic and technological interest. We developed a wet-chemical route to synthesize monodisperse bent rigid silica rods by controlled perturbation of emulsion-templated growth. The bending angle of the rods can be tuned in a range of 0-50° by varying the strength of perturbation in the reaction temperature or pH in the course of rod growth.

Interfacial Structure of a Liquid Crystal/Nanoparticle Nanocomposite Studied by X-ray Scattering: Indirect Evidence for the Role of Faceting of the Nanoparticles.

The interfacial structure in a liquid crystal/nanoparticle nanocomposite is dictated by the type of nanoparticle and its functionalization compound. Nanocomposites consisting of smectic liquid crystals and nanoparticles have been studied for their applications in devices such as photovoltaics and to model biological devices. With the use of a model system, this paper presents evidence of an interfacial structure close to the vicinity of the nanoparticles that is more disordered than that of the bulk liquid crystal but is still in the smectic phase, and it seems to follow the faceting of the structure the nanoparticles adopt when they coalesce or recluster after the liquid crystal is added.

Effects of magnetic nanoparticles with different surface coating on the phase transitions of octylcyanobiphenyl liquid crystal.

The impact of magnetic nanoparticles with different surface coating upon the isotropic-to-nematic and nematic-to-smectic- A phase transitions of the liquid crystal octylcyanobiphenyl is explored by means of high-resolution adiabatic scanning calorimetry. A shrinkage of the nematic range is observed, which is strongly dependent on the surface coating of the nanoparticles. The isotropic-to-nematic transition remains weakly first order while the nematic-to-smectic- A is continuous with the effective critical exponent alpha values (0.