Two azo substituted achiral bent-core mesogens have been synthesized. Optical polarizing microscopy and synchrotron X-ray scattering studies of both compounds reveal the existence thermotropic uniaxial biaxial nematic three smectic phases at different temperatures in these single component small molecule systems. The transition from to phase is confirmed be second order. transitions underlying between barely discernible heat capacity signatures thus are also

Lyotropic chromonic liquid crystals (LCLCs) are formed by molecules with ionic groups at the periphery that associate into stacks through noncovalent self-assembly while in water. The very existence of nematic (N) phase typical LCLC, dye Sunset Yellow (SSY) is a puzzle, as correlation length associated stacking, measured X-ray experiments, too short to explain orientational order Onsager model. We propose aggregates can be more complex than simple rods and contain "stacking faults" such...

A new class of nanoscale light‐harvesting discotic liquid crystalline porphyrins, with the same basic structure best photoreceptor in nature (chlorophyll), was synthesized. These materials can be exceptionally aligned into a highly ordered architecture which columns formed by intermolecular π–π stacking are spontaneously perpendicular to substrate. The homeotropic alignment, well confirmed synchrotron X‐ray diffraction, could not only provide most efficient pathway for hole conduction along...

In this paper, a direct switching between transparent (or reflecting) planar (P) state to an opaque transparent) focal conic (FC) and vice-versa of polymer free bistable cholesteric light shutter without any homogeneous polyimide (PI) layer, is demonstrated based on the sign inversion dielectric anisotropy dual frequency liquid crystal (DFLC). The was achieved by applying square wave field at low (1 kHz) high (50 frequency. As result, DFLC sustains bright dark states in electric off exhibits...

The highly ordered nanostructured thin film consisting of the liquid crystalline porphyrin−fullerene blend was prepared by simple thermal annealing. nature their homeotropic alignment is well-confirmed. concept demonstration provides new insight on fabricating defect-free large area films with directed molecular arrangement.

We use optical and fluorescence microscopy, densitometry, cryo-transmission electron microscopy (cryo-TEM), spectroscopy, synchrotron X-ray scattering to study the phase behavior of reversible self-assembled chromonic aggregates an anionic dye Sunset Yellow (SSY) in aqueous solutions crowded with electrically neutral polymer polyethylene glycol (PEG) doped salt NaCl. PEG causes isotropic SSY condense into a liquid-crystalline region high concentration aggregates, coexisting PEG-rich (I)...

Dense multicomponent systems with macromolecules and small solutes attract a broad research interest as they mimic the molecularly crowded cellular interiors. The additives can condense align macromolecules, but do not change degree of covalent polymerization. We chose lyotropic chromonic liquid crystal reversibly non-covalently assembled aggregates much softer system, reminiscent “living polymers”, to demonstrate that neutral charged cause condensation ensuing orientational positional...

In situ homeotropic alignment is achieved by photochromic trans- to cis-isomerization of an azo-dye doped in a nematic host. The augmented dipole moment the cis-isomer formed under UV-irradiation expedites molecular assembly into crystalline aggregates. Subsequent deposition aggregates creates roughened surface and induces anchoring transition from initial planar LCs.

Abstract Smart windows are very attractive because they not only provide comfortable indoor conditions for cars and buildings, but also protect privacy. However, current smart have problems such as high energy consumption, slow response time, poor stability. To solve these problems, a single‐step dual stabilization (SSDS) is newly proposed the fabrication of robust liquid crystal (LC) switching fast at low voltage. Upon irradiating ultraviolet light on selected area nematic (N) LC optical...

A homologous series of shape-persistent V-shaped molecules has been designed to form the biaxial nematic phase. Phenyleneethynylene moieties are attached a bent fluorenone unit create an apex angle about 90°, which is determined from single crystal structure. Two mesogens, one symmetric and another unsymmetric, have synthesized by attaching cyano group or both peripheral phenyl units, respectively. These groups introduce local dipoles essential for formation phases. The tendency crystalline...

The novel nanoscale discotic liquid crystal porphyrin with partial chain perfluorination, which has the same basic structure as best photoreceptor in nature (chlorophyll), shows an exceptionally enhanced tendency to self-assemble into ordered nanostructure. Defect-free homeotropically aligned fluorinated thin films were, for first time, fabricated and characterised. ability large π-conjugated molecules highly nanostructure via perfluorination provides new insight bottom-up nanofabrication of...

Surface pinning effect of the optically isotropic, blue phase liquid crystal (BPLC) has been studied. Polycrystalline, platelet, multi-domain topological defects without surface treatment have transformed to uniform monodomain in rubbed surfaces cell. The operating voltage was reduced by 27%, owing a dramatic increase Kerr constant. Hysteresis 63%, whereas transmission efficiency gets doubled. anchoring on plays significant role elastic free energy, coherence length and defects. BPLC...

Carbon quantum dots (CQDs) have been extensively explored in diverse fields because of their exceptional features. The nanometric particles with photoluminescence (PL) benefit various optical and photonic applications. However, the majority previous reports mainly focused on either unpolarized or circular-polarized (CP) PL. Linearly polarized (LP) emission CQDs is limited isometric shape difficulties macroscopic orientation control. Herein, we report syntheses anisometric facile control...

We report a study of polymer network morphology in planar diffraction gratings formed from polymer-stabilized cholesteric liquid crystals. Photopolymerizing mesogenic monomer yields regular sawtooth morphology, composed sheets running at an acute angle between thick, uniformly aligned bundles which reside on the opposing substrates. To explain this and evidence two grating vectors pattern, we propose model for liquid-crystal director where out-of-phase twists surfaces gear into interior...

The first examples of electrically switchable and photo-responsive mesophases in a novel class bent-core azo compounds, consisting only five aromatic rings no imino functionality (–CHN–), are reported. have been identified as B1, B2 new mesophase, Bx, on the basis results polarizing optical microscopy, differential scanning calorimetry, X-ray diffraction, electro-optical response. Preliminary but profound photo-induced effects transition temperature from isotropic to mesophase one compounds...

The dye sunset yellow (SY) forms columnar aggregates via $\ensuremath{\pi}\text{\ensuremath{-}}\ensuremath{\pi}$ stacking in aqueous solutions. These develop orientational and translational order at elevated concentrations to exhibit the nematic (N) (C) mesophases. Positional-order correlation lengths of directions parallel perpendicular direction were measured as functions temperature, concentration, ionic content solutions with synchrotron x-ray scattering magnetically aligned samples....

The results of a recent investigation the nematic biaxiality in bent-core mesogen (A131) are apparent disagreement with earlier claims. Samples A131 used two studies were investigated polarized optical microscopy, conoscopy, carbon-13 NMR, and crossover frequency measurements. demonstrate that textural changes associated growth biaxial order appear at $\ensuremath{\sim}149\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$. Maltese cross observed conoscopic figure gradually splits into...

Abstract The nematic phase occurring in bent-core (or banana-shaped) molecule systems is conducive to the occurrence of biaxial (Nb) due inherent molecular shape. tendency molecules stabilise a layered (smectic) structure poses one difficulties obtaining thermotropic Nb phase. To investigate factors favouring formation phase, number liquid crystals derived from 1, 3-phenylene central bent motifs were synthesised. Results an investigation into influence nature and position substitutions on...

We describe a novel method for liquid crystal (LC) alignment using nano-patterns of electrically conductive indium–tin oxide (ITO) layers with high resolution (ca< 20 nm) and aspect ratio (ca 10), fabricated based on the secondary sputtering phenomenon. The ITO pattern developed in this manner not only provides anchoring energy comparable to that rubbed polyimides, but also maintains its low resistivity as an electrode. As result, patterned can function electrode layer at same time, which...

The effect of well-established homeotropically and homogeneously aligning polyimides, developed for calamitic liquid crystals, on the alignment nematic phases bent-core mesogens was investigated using polarizing optical microscopy conoscopy. Two SE7792 S659, were used to align three mesogens. mesogens, with an azo group in one their arms, are found a manner similar while fluorenone core based mesogen counter-intuitively aligns S659 coated surface SE7792. Attractive interactions between...