We have investigated a new form of polymer dispersed liquid crystals (PDLC) electro-optical films comprised of blue phase liquid crystal and polymer prepared by the solvent evaporation method. In this method, polymer dispersed blue phase (PDBP) films, which were laminated between two indium-tin-oxidecoated conductive substrates, demonstrated two switching modes between light scattering and transparent states in response to an applied electric field across the film. The electro-optical properties of PDBP liquid crystals can be altered by changing the concentrations of liquid crystal and polymer. The compositions, film preparations, physical and morphological behaviors, and electro-optical properties of PDBP films are described.
We report on dispersion of a small amount of colloids in a blue phase liquid crystal, and the blue-phases were found to exhibit extended temperature range. The stabilized temperature range of the blue phase was a function of their most effective concentration, different sizes of colloid particles and shape of colloidal particles. The temperature range was probed and determined and the temperature range of the blue phases was found to decrease as the colloidal particle size increased. Additionally, the temperature dependent of Bragg wavelength peak was found to redshifted in the colloidal-BP mixtures. The electro-optical results, especially the switching voltage and response time suggested that concentration and size of dispersed colloids modified the elastic energy of the blue phase liquid crystal composites and led to a lower switching voltage.
Blue phases are types of liquid crystal phase which can appear in a narrow temperature range between a chiral
nematic phase and isotropic liquid phase. Blue Phase (BP) liquid crystals have been known to exist in a small
temperature range. Recently, broadening the temperature range of a BP liquid crystal has occurred by using a
mixture of nematic bimesogenic liquid crystals or by polymerizing a small amount of monomer in a BP to
stabilize the cubic lattice against temperature variation. In this study, we report a low switching voltage
polymer stabilized blue phase (PSBP) liquid crystal device. We showed the stabilization of blue phases over
a temperature range of 30.4 °C including room temperature. We observed the temperature independent of
Bragg wavelength. Furthermore, the polymer effect on the electo-optic properties of a self assembled nanostructured
blue phase liquid crystal composites have been investigated. As well as the ratio between two
monomers, the overall monomers concentration is controlled.