Nanostructured Polymer-Dispersed Liquid Crystals Using a Ferroelectric Smectic A Liquid Crystal.

Nanostructured polymer-dispersed liquid crystals (nano-PDLCs) are transparent and optically isotropic materials in which submicron-sized liquid crystal (LC) domains are dispersed within a polymer matrix. Nano-PDLCs can induce birefringence by applying an electric field (-field) based on the reorientation of the LC molecules. If nano-PDLCs are utilized as light-scattering-less birefringence memory materials, it is necessary to suppress the relaxation of the LC molecule orientation after the removal of the -field.

Ferroelectric Smectic C Liquid Crystal Phase with Spontaneous Polarization in the Direction of the Director.

In the previous study, the existence of an unidentified ferroelectric smectic phase is demonstrated in the low-temperature region of the ferroelectric smectic A phase, where the layer spacing decreases with decreasing temperature. In the present study, the phase is identified by taking 2D X-ray diffraction images of a magnetically oriented sample while allowing it to rotate and constructed a 3D reciprocal space with the sample rotation angle as the third axis for the whole picture of the reciprocal lattice vectors originating from the smectic structure. Consequently, circular diffraction images are obtained when the reciprocal lattice vectors are evenly distributed on the conical surface at a certain inclination angle in the reciprocal space.

Exploring the Impact of Linkage Structure in Ferroelectric Nematic and Smectic Liquid Crystals.

The liquid crystal molecule 3-fluoro-4-(3,4,5-trifluorophenyl)phenyl 2,6-difluoro-4-(-5-n-propyl-1,3-dioxane-2-yl)benzoate (DIO) has attracted considerable interest owing to its unique ferroelectric nematic phase and extraordinarily high dielectric constant. To expand the DIO series, novel analogs with 1,3-dioxane units converted to ester units (EST analogs) were synthesized, and their physical properties were characterized. The EST analogs exhibited ferroelectric phases similar to those of the corresponding DIO analogs.

Fluid Layered Ferroelectrics with Global C Symmetry.

Ferroelectricity in fluid materials, which allows free rotation of molecules, is an unusual phenomenon raising cutting-edge questions in science. Conventional ferroelectric liquid crystals have been found in phases with low symmetry that permit the presence of spontaneous polarization. Recently, the discovery of ferroelectricity with high symmetry in the nematic phase has attracted considerable attention.

Convenient chirality transfer from organics to titania: construction and optical properties.

Polyethyleneimine (PEI) complexed with chiral d- (or l-) tartaric acid (tart) in water can self-organize into chiral and crystalline PEI/tart assemblies. It has been previously confirmed that the complexes of PEI/tart could work as catalytic/chiral templates to induce the deposition of SiO nanofibres with optical activity but without outwards shape chirality such as helices. In this work, we found that the templating functions of PEI/tart were still effective to prompt the deposition of TiO to form chiral PEI/tart@TiO hybrid nanofibres under aqueous and room temperature conditions within two hours.

Reworkable Polyhydroxyurethane Films with Reversible Acetal Networks Obtained from Multifunctional Six-Membered Cyclic Carbonates.

Multifunctional 6-membered cyclic carbonates (6-CCs) comprising acetal structures have been synthesized via phosgene-free routes and utilized for the fabrication of reworkable networked poly(acetal-hydroxyurethane) (PAHU) films. Dibenzoyl-protected di(trimethylolpropane) (DTMP) reacts with multifunctional aldehydes derived from nonexpensive alcohols to afford protected multifunctional DTMPs. After deprotection, the multifunctional DTMPs can react with diphenyl carbonate to efficiently form multifunctional 6-CCs.

Nanosheet-stacked chiral silica transcribed from metal ion- and pH-tuned supramolecular crystalline complexes of polyamine-D-glucarate.

D-glucaric acid (D-Glc) associates with linear poly(ethyleneimine) (PEI) through hydrogen bonding and electrostatic interactions in aqueous media to form nanostructured crystalline PEI/D-Glc/H2O complexes with PEI/D-Glc/H2O ratios of 2:1:2. These complexes can serve as templates for silica depositions from hydrolytic condensation of tetramethoxysilane to guide morphologically duplicated silica under very mild conditions. Their microscale morphologies are tunable by use of the crystalline complexes regulated in the different pH of the PEI/D-Glc solutions.

Controlled formation of polyamine crystalline layers on glass surfaces and successive fabrication of hierarchically structured silica thin films.

The formation of silica films on the glass plate whose surface was precoated by crystalline linear poly(ethylenimine) (LPEI) in advance was systematically investigated via controlling the surface-specific crystallization of the LPEI on the glass plate. Immersing glass substrates into a hot aqueous solution of LPEI containing additives such as transition metal ions and acidic compounds and retaining them on 30 °C for desired periods resulted in the formation of crystalline LPEI layers on the substrates. Subsequently dipping this LPEI-coated glass into silica source solutions afforded successfully hierarchically structured silica film which coated continuously the surface of the substrates.

Lipid-packaged linear iron(II) triazole complexes in solution: controlled spin conversion via solvophobic self-assembly.

Linear Fe(II) 1,2,4-triazole complexes with lipid counteranions are newly developed. These complexes show sharp and reversible spin conversion in toluene, with temperatures significantly higher (by 20-100 K) than the spin crossover temperatures observed in the crystalline states. This is accounted for in terms of increased metal-ligand interactions in organic media, which is caused by solvophobic compaction of charged coordination chains.