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• A series of novel bis-tolane luminescence liquid crystals (LLCs) with SO 2 CF 3 as terminal were firstly achieved. • Adjustable tri-response thermochromic fluorescent materials (TFMs) were obtained. • TFMs of (CH 3) 2 N-2F-SO 2 CF 3 exhibit excellent character which promise candidate for information encryption. A series of novel bis-tolane luminescence liquid crystals (LLCs) with SO 2 CF 3 as terminal were first time achieved. These SO 2 CF 3 -based LLCs act as thermally responsive emission sources combined with a series of thermosensitive long-chain carboxylic acids with self-crystallization properties to obtain adjustable tri-response thermochromic fluorescent materials (TFMs). Notably, TFMs of (CH 3) 2 N-2F-SO 2 CF 3 exhibit excellent temperature sensitivity and tri-response thermochromic fluorescent character, which display outstanding thermochromic properties from 45 °C to 165 °C. These TFMs displayed an intuitively evident orange under ultraviolet (UV) irradiation then changed to orange-yellow color after adding long-chain carboxylic acids. Notably, it changed to yellow-green when heated to the long-chain carboxylic acids melting point of these phase change materials, further emitting a blue color at the mesophases transition when increasing temperature at 165 °C of (CH 3) 2 N-2F-SO 2 CF 3. Interestingly, the various thermochromic abilities and stimuli-responsive fluorescence of these TFMs could be regulated by substituents of LLCs and long-chain carboxylic acids. Therefore, such tri-response and high-contrasted thermochromic fluorescent character of TFMs are different from previous reports which promise candidates for information encryption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Misinformation of the experimental data in a recent publication is discussed. • Parasitic effects (artefacts) influencing the dielectric results are also deliberated. • Representation of Cole-Cole diagram with the dielectric data is scrutinised. A research article titled as "Hydrogen-bonded liquid crystal complexes: A comprehensive study of structure, behaviour and potential applications" has been recently published by Meddeb et al., J. Mol. Liq. 395 (2024) 123838. Authors have reported and analysed thermodynamic and dielectric studies on highly ordered SmB and SmG mesophases in 14OBAF/DABCO complexes. But explanations of the dielectric data reported on the material are flawed based on various facts. Unintended wrong interpretations by the authors in reporting and explaining the thermodynamic and dielectric results are discussed here. Influence of various artefacts on acquired dielectric data has also been discussed in order to avoid such problems in further reports. [ABSTRACT FROM AUTHOR]

Nano-porous active layers templated by hexagonal lyotropic liquid crystal (HLLC) offer a continuous water pathway, rendering them promising for membrane separation applications of high performance. The surface properties, such as surface roughness, hydrophilicity and pore size, of commercially available ultrafiltration membranes usually need to be optimized to better support the active layer. Here, we apply a facile yet potent thermal treatment process to a polyacrylonitrile ultrafiltration (UPAN) substrate and form a continuous HLLC separation layer. The enhancement in water filtration performance is largely influenced by the surface roughness of the substrates. As the temperature increases, the UPAN substrates become rougher due to approaching the glass transition temperature of polyacrylonitrile. This leads to a denser HLLC active layer with smaller pores. For the membranes treated at a temperature of 100 °C, their water flux reaches 17 L/m2h, which is 10 times higher than that of the membranes treated at 85 °C, and the PEG4000 rejection increases by almost 50 % from 42 % to 59 %. This heat treatment process offers a novel approach to fabricate mesophase-templated active layers with adjustable pore sizes, thus advancing membrane separation techniques. [Display omitted] • A continuous hexagonal lyotropic liquid crystal templated active layer was successfully formed on the thermally treated polyacrylonitrile ultrafiltration substrates. • High surface hydrophilicity and small surface pore size of the thermally treated substrates facilitate the formation of the active layer. • Hexagonal mesophase with a smaller lattice parameter was formed on a rougher substrate, leading to the formation of an active layer with a smaller pore size and higher rejection performance. [ABSTRACT FROM AUTHOR]

This study employs Molecular Dynamics simulations to enhance the structural characterization of sphere mixture systems, focusing on local order parameters to identify order-disorder transitions within lamellar and hexagonal mesophases. The structural characterization included the use of neural networks and the search for clusters with topological order. We have identified the order-disorder transition at a characteristic temperature T OD , effectively captured by the structural parameters analyzed. Below T OD , the system organizes into an ordered mesophase, while above this temperature, it transitions into an isotropic liquid state. Moreover, within the isotropic region, we observe that the liquid begins to form clusters. This clustering phenomenon becomes evident below a specific temperature, denoted as T ⁎. At T ⁎ , there are noticeable changes in the volume versus temperature curves, indicating a process of micellization or clustering in the system. The structural parameters used in our study also register this behavioral change at T ⁎ , further supporting the occurrence of this phenomenon. Additionally, our analysis of the overlap in detecting ordered particles between the two structural parameters using the Sørensen-Dice similarity coefficient reveals a significant spatial correlation in the isotropic phase, with a correlation higher than what would be expected in a random case. This indicates that both neural networks and topological cluster classification detect statistically similar ordered regions in the isotropic phase, highlighting the clustering. Our findings reveal that the structural parameters effectively capture both the order-disorder transition at T OD and the clustering process at T ⁎. These results provide valuable insights into the self-assembly mechanisms and phase behavior in this soft-sphere model, advancing our understanding of self-assembly processes in material science, particularly in exploring phase behavior in mesogenic nanoparticle systems. • Advanced structural parameters in simplified sphere models for analyzing self-assembly processes. • Machine Learning and Topological Cluster Classification for improved short-range structural analysis. • Uncovering local order in isotropic phases to better understand clustering in isotropic phase behavior. [ABSTRACT FROM AUTHOR]

[Display omitted] • Misinterpretation of the various experimental data in a recent publication is discussed. • Parasitic effects have highly influenced the dielectric data. • Testing criteria to validate the dielectric data have been discussed. Recently, a work entitled "Synthesis, thermal, dielectric and electro-optic properties of new series of fluorinated hydrogen-bonded liquid crystals" is published by M. Derbali et al., in J Mol Liq, 367 (2022) 120510. Authors reported SmA and SmC mesophases in the synthesised liquid crystalline materials. However, dielectric data reported here are erroneous when tested even from some fundamental aspects. Inadvertent omissions by the authors in presenting and explaining the dielectric results in terms of frequency dependent permittivity and loss are discussed here so that appropriate precautions may be taken by the readers to avoid such fundamental gross mistakes. Some problems related to other studies are also discussed in brief. [ABSTRACT FROM AUTHOR]

• New LC dimers with azo or azomethine naphthalene synthesized and characetrized. • Even-spacer dimers are nematogenic, whereas odd-spacer dimers are non-mesogenic. • Structure-property relationship discussed for synthesized dimers of both series. • NpAmDn series exhibits wider mesophase ranges than NPAzDn. • DFT analyzed, structure optimized, and vibrational frequencies studied. • Azo dimers undergo photoisomerization when exposed to 360 nm light. The reactions of different α,ω-dibromo alkanes with (E)-4-(naphthalen-2-yldiazenyl)phenol and (E)-4-(naphthalen-2-ylimino)methyl)phenol, respectively, led to the synthesis of two new homologous series of liquid crystalline symmetrical dimers with azobenzene or azomethine central linkage and containing the naphthalene moiety as a rigid core. Spectroscopic techniques like FT-IR, 1H NMR, 13C NMR and elemental analysis confirmed their structure. These dimers exhibited mesomorphic phases, studied through POM and DSC. Their photophysical behaviour was explored using UV–visible spectroscopy. Remarkably, dimers with even spacer units (n = 2, 4, 6, 8, 10, 12) displayed excellent liquid crystalline properties as nematic phases, with extended mesophase lengths and thermal stability for both series. The study revealed the vital role of spacer length in determining liquid crystalline behaviour. The computational studies employed the B3LYP method and electron density method for optimization. [Display omitted] [ABSTRACT FROM AUTHOR]

The exceptional band-edge lasing from dye-doped cholesteric liquid crystals (DD-CLCs), which can be easily fabricated by blending chiral molecules with nematic liquid crystals, showcases versatile tuning possibilities. In this work, we employed (ISO-(6OBA) 2) with high helical twisting power (HTP) as the chiral molecule in the fabrication of DD-CLCs, ensuring superior tuning possibilities and operational stability at high temperatures. By thermally controlling DD-CLCs with a 5 wt% chiral molecule, the band-edge lasing peak exhibited a noticeable red shift with increasing temperature, demonstrating a tuning range of 106 nm as the temperature rose from 20 to 90 °C. In operation at 78 °C, the longest lasing peak of 692.7 nm was achieved from DD-CLCs with 4 wt% ISO-(6OBA) 2. Furthermore, the long-term stability of band-edge lasing from DD-CLCs was proven during a three-hour monitoring period at a high operating temperature above 50 °C. • First demonstration of band-edge lasing from DDCLCs using ISO-(6OBA)2 as the chiral molecule. • High-temperature operation of DDCLCs at 90 °C to produce band-edge lasing. • Tuning of the band-edge lasing peak by approximately 106 nm through thermal control of DDCLCs. • Three-hour stable operation of band-edge lasing in operation DDCLCs at 75 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] Responsive and adaptive soft-matter systems represent an advanced category of materials with potential applications in drug delivery. Among these, liquid crystals (LCs) emerge as multifunctional anisotropic scaffolds capable of reacting to temperature, light, electric or magnetic fields. Specifically, the ordering and physical characteristics of thermotropic LCs are primarily contingent on temperature as an external stimulus. This comprehensive review aims to bridge a notable gap in the biomedical application of thermotropic mesogens by exclusively focusing on drug delivery. Anticipated to inspire diverse ideas, the review intends to facilitate the elegant exploitation of controllable and temperature-induced characteristics of LCs to enhance drug permeation. Here, we delineate recent advancements in thermally-driven LCs with a substantial emphasis on LC monomer mixtures, elastomers, polymers, microcapsules and membranes. Moreover, special emphasis is placed on the biocompatibility and toxicity of LCs as the foremost prerequisite for their application in healthcare. Given the promising prospect of thermotropic LC formulations in a clinical context, a special section is devoted to skin drug delivery. The review covers content from multiple disciplines, primarily targeting researchers interested in innovative strategies in drug delivery. It also appeals to those enthusiastic about firsthand exploration of the feasible biomedical applications of thermotropic LCs. To the best of our knowledge, this marks the first review addressing thermotropic LCs as tunable soft-matter systems for drug delivery. [ABSTRACT FROM AUTHOR]

The correlation of the anisotropic texture and (002) the molecular stacking property of spinnable mesophase pitch (SMP) was closely examined. SMP was found to be a specific solution consisting of mesogenic and solvent components, and the mesogenic component was composed of a cluster unit of (002) stacked molecular sheets. The anisotropic texture of SMP was strongly correlated with the height of (002) molecular stacking. When the concentration ratio of the mesogenic component to the solvent component was higher than the threshold concentration, the SMP always had 100 vol% anisotropic texture and a similar or larger number of stacked (002) sheets compared with its mesogenic component in both the solid and molten states. The solvent component, in both lamellar and hexagonal phases, assisted orientation of mesogenic molecules and rearrangement of mesogenic cluster units, thereby inducing a higher degree of graphitization than that of the solvent-free mesophase pitch. A schematic phase model of SMP was proposed based on a lyotropic liquid crystalline system and a hierarchical domain model. [Display omitted] [ABSTRACT FROM AUTHOR]

Increasing the toughness of poly(lactic acid) (PLA), i.e., simultaneously increasing both the tensile strength and ductility, remains a major challenge. In this study, fully bio-based PLA blends with polydecalactone (PDL)-grafted cellulose copolymer (CgPD) were prepared and comprehensively analyzed to enhance the toughness of the PLA matrix. The blends were found by FT-IR and solid-state 1H NMR to be physically intact and miscible at the sub-twenty-nanometer scale. The WXRD and DSC analyses indicated that the addition of the alkyl-branched CgPD imparts a more structurally disordered PLA mesophase state to the prepared PLA_CgPD bio-blends. UTM analysis was used to characterize the macroscopic mechanical properties of the PLA_CgPD bio-blends. Both the tensile strength and elongation properties were simultaneously improved with the addition of 1 wt% CgPD loading amount to PLA (PLA_CgPD1). This study experimentally demonstrates that the enhanced mechanical properties of PLA_CgPD1 are closely related to the existence of more ordered PLA mesophases induced by the introduction of an optimal amount of CgPD into the PLA matrix. The blending of the PLA and alkyl-branched polydecalactone-grafted cellulose (CgPD) can impart an enhanced tensile toughness to the PLA matrix [Display omitted] • A series of bio-based PLA/cellulose graft copolymer (CgPD) blends were prepared. • The prepared PLA_CgPD blends were found to be physically intact and miscible. • The addition of CgPD induced a more structurally disordered PLA mesophase. • The enhanced tensile properties were related to the more ordered PLA mesophases. [ABSTRACT FROM AUTHOR]

• A β-Ga 2 O 3 crystal with a diameter of 30 mm was grown by the LDFZ method. • The beam profile was adjusted to heat the molten zone locally and intensively. • Three beam profile patterns were switched with increasing the crystal diameter. • Proper beam profile and proper diameter of the feed rod keep the molten zone stable. To investigate the effect of high-power laser heating on the floating zone (FZ) method, a crystal of β-Ga 2 O 3 was grown by the LDFZ method using a newly developed optical system equipped with a 20-kW laser diode (LD) system as a heat source. The growth started from a twin-free seed crystal with a diameter of 7 mm and the diameter of the crystal was increased gradually up to 30 mm. With increasing the diameter of the crystal, three patterns of the beam intensity profile were switched to heat the whole of the molten zone locally and intensively. The intensity profile of the five beamlets irradiating the sample was adjusted with a combination of the zooming by the optical system and the partial blocking by the alumina cylinder. By the proper tuning of the beam profile and the proper selection of the diameter of the feed rod, the molten zone was kept stable against gravity. The obtained crystal has a layer texture without clear facets or cracks. It almost conserves the crystallographic direction of the seed crystal but is twinned except for a twin-free region near the seed crystal. [ABSTRACT FROM AUTHOR]

Mesophase pitch is a high-quality precursor for the synthesis of high-performance pitch-based carbon fibers. The mesophase content, texture and softening point are the most important factors for the structure, properties and spinnability of mesophase pitch (MP). Herein, we report a novel approach for the preparation of mesophase pitch with high anisotropic content and low softening point by AlCl 3 catalytic pyrolysis in the presence of isopropyl chloride (PrCl). The variation of anisotropic content and mesophase texture under different PrCl additions and the effect of the introduction of isopropyl on the molecular stacking of aromatic lamellar molecules were investigated. The results confirmed that, except for their role in improving catalytic activity, carbocation co-catalysts can improve the structure and molecular assembly of aromatic molecules through the introduction of alkyl groups. The reaction of isopropyl chloride (PrCl) as a co-catalyst catalyzed pyrolysis of medium-temperature coal pitch at 370 ℃ for 8 h produced a bulk mesophase with a content close to 100 %. Compared to the AlCl 3 system (without PrCl), the AlCl 3 -PrCl system can catalyze the preparation of mesophases at lower temperatures. In addition, it is logical that the introduction of isopropyl group significantly increases the stacking spacing of the mesophase pitch layer molecules, which can effectively improve the mobility of the aromatic layer molecules resulting in the growth of mesophase. The fusion texture and anisotropic content of mesophase pitch were significantly improved by replacing the nucleophilic reagent of the AlCl 3 -catalyzed system. This work provides feasible ideas for the preparation of high-performance coal tar based mesophase pitch. • Isopropyl chloride (PrCl) - aluminum chloride (AlCl 3) catalyzed the preparation of mesophase. • PrCl-15% has 100% mesophase content and Bulk mesophase texture. • Isopropyl not only catalyzes the reaction as a carbon cation, but also introduces methyl groups into pitch to enhance aromatic molecules slip. [ABSTRACT FROM AUTHOR]

In liquid crystals doped with aerosil nanoparticles, the state induced by applying voltage or a magnetic field stays remembered after removing the power. The ability to remember the induced state after removing the power is known as non-volatile memory effect. The present paper describes how the magnitude of voltage and magnetic field affects the memory effect in the nematic phase of liquid crystal 4-cyano-4′-pentylbiphenyl doped with aerosil nanoparticles and with a combination of aerosil and magnetic goethite nanoparticles. Capacitance measurements revealed increasing in memory when the magnitude of voltage and magnetic field is increased. Applying fields with various magnitudes provides the possibility of fabrication a multilevel memory device based on the response to electric or magnetic field. The memory can be erased, and the initial state can be restored by heating the composites to the same temperature. • Memory effect in nematic composites induced by electric and magnetic field was observed. • The magnitude of memory effect can be tuned by intensity of electric or magnetic field. • Heating the composite results in erasing the memory and reaching the initial state. • Potential use as a multilevel memory device is proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Silver nanoparticles have been dispersed in a liquid crystalline material. • Nematic phase of the material has stabilized in the presence of nanoparticles. • Nematic-isotropic transition temperature has increased due to enhanced ordering. • Dielectric anisotropy has also significantly enhanced in the composite systems. • Switching voltage for electro-optical application has drastically decreased. Nanocomposites of 4-(trans -4-n-hexylcyclohexyl) isothiocyanatobenzene nematic liquid crystals and silver nanoparticles have been prepared. UV absorption spectroscopy, Fourier transform infrared and Raman spectroscopies were used to characterize the morphology of silver nanoparticles (Ag-NPs). Thermodynamic, optical, and dielectric studies have been done to explore the change in the physical parameters of the composites with respect to the pure sample. Due to dispersion of silver nanoparticles, transition temperature, associated enthalpy and order parameters of the nanocomposites have increased. Dielectric study shows enhanced dielectric anisotropy for Ag-NPs dispersed nanocomposites. The relaxation frequency of an observed mode has shifted towards high frequency region for the nanocomposites. Optical band gap for pure and nanocomposites samples has been estimated from UV absorption peaks and it is found that optical properties of the nanocomposites are almost invariant. Threshold (switching) voltage, rotational viscosity and splay elastic constant for pure and dispersed samples have also been obtained from electro-optical studies. [ABSTRACT FROM AUTHOR]

Alternating-current poling (AC-Poling) has attracted wide interests in enhancing piezoelectric performance of ferroelectric single crystals. However, the mechanism of phase transformations and domain morphology underlying AC-Poling has not been thoroughly investigated. In this work, we have systematically studied the AC-poling effect on domain structures and piezoelectric properties in the relaxor ferroelectric single crystals of 0.24Pb(In 1/2 Nb 1/2)O 3 –0.44Pb(Mg 1/3 Nb 2/3)O 3 –0.32PbTiO 3. It is shown that the piezoelectric constant (d 33) and permittivity (ε 33) are greatly enhanced via [001]-AC-poling compared to DC-poling, related to the presence of modified domain configurations as indicated previously. For [110]-oriented specimens, the piezoelectricity through AC-poling is only half as that for the DC-poled single crystals. We attribute this to the transition from the monoclinic-B phase to an orthorhombic phase under AC-poling, confirmed by synchrotron radiation X-ray diffraction and piezo-response force microscopy. The transition to the orthorhombic phase is likely a consequence of lower Gibbs energy. This study on orientation-dependent characteristics of AC-poling for PIN-PMN-PT single crystals will guide the development of AC-poling technology in applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The modulation and spectral characteristics of self-organized ensembles of nematic domains with the disclination lines non-aligned and aligned in a magnetic field have been studied using an electric field. The obtained experimental voltage dependences of the light transmission agree well with the dependences calculated using the model considerations. These dependences have been compared with the electro-optical characteristics of a homogeneous planar nematic layer. The amplitude component of the optical transmission determined by light scattering and the oscillating component caused by the phase modulation have been examined. The effect of the spectral dispersion of transmission on the electro-optical characteristics of domain ensembles has been evaluated. [Display omitted] • SEND is a promising material for light modulators. • Light modulation in SEND occurs due to interference effect in the absence of polarizers. • Light scattering in SEND is significantly reduced when disclination lines are ordered in a magnetic field. • The spectral dispersion of SEND light transmission is controlled by electrical voltage. [ABSTRACT FROM AUTHOR]

The adverse effect of draw-down ratio (DDR) during melt-spinning of mesophase pitch on resulting properties of carbon fibers (CFs) is reported. Precursor fibers were obtained using spinneret capillaries of various diameters. For CFs with equivalent diameters (ranging between 8 and 13 μm), the tensile strength of CFs increased from 1.4 to 2.3 GPa as the DDR of precursor fibers decreased from 189 to 14. This is contrary to that observed for CFs derived from polyacrylonitrile precursor, where strength increases with increasing precursor fiber DDR. Raman spectroscopy revealed an inverse relationship between pitch fiber DDR and CF coherence length (increase from 58 to 85 nm when DDR decreased from 189 to 14). Further, x-ray diffraction results confirm a larger CF crystalline orientation with decreasing DDR. Thus, a smaller DDR during mesophase spinning could facilitate intra-crystalline graphitic-plane orientation and decrease defects in the inter-crystalline regions along fiber axis in resulting CFs, leading to increased strength (a defect-controlled property). Thus, while it is generally known that tensile strength increases with decreasing CF diameter, for mesophase pitch-based carbon fibers this relationship is not fully valid if the diameter reduction is obtained by merely increasing the draw-down ratio of precursor fibers during melt-spinning. Image 1 [ABSTRACT FROM AUTHOR]

• Electric-field induced bending occurs in nematic elastomers with orientation gradient. • Bending shapes strongly depend on the orientational distribution of the director. • Analytical and finite element solutions for the bending behavior are obtained. • Bending curvature is enhanced by adjusting the linearly varying director distribution. • Bending curvature can be increased by > 300% of that of the splay-bend sample. Swollen nematic elastomers can deform under an applied electric field due to the electro-opto-mechanical coupling effect. This unique coupling mechanism causes the nematic elastomer to exhibit larger deformations under weak electric fields as compared to many conventional dielectric elastomers. Further, the electric-field induced deformations can be controlled by proper design of the initial liquid crystal director. Based on a simple electro-mechanical-director coupled model under small strain assumption, finite element simulations are conducted for beam-shaped thin strip samples with orientation gradient initially. Approximate analytical solutions are obtained for the electric potential, director reorientations, stress, and strain under weak electric fields. Using the first- order shear strain beam theory, the analytical solutions for the bending deflections are determined for beams with various boundary conditions, and they are only governed by the spontaneous curvature and the average transversal spontaneous shear resulting from the spontaneous strains induced by the applied electric fields. Optimization of the electric-field induced bending curvature leads to linearly-varying director distributions, which have much larger bending curvatures than that exhibited by the most commonly studied splay-bend distribution. Moreover, we demonstrate that bending shapes strongly depend on the orientational distribution of the director. Thus, a proper design can be used to effectively control the electric-field induced deformation and bending. Overall, we believe that our study is potentially useful to create desired and optimized bending for electrically-triggered sensors and actuators. [ABSTRACT FROM AUTHOR]

We conducted replica exchange Monte Carlo simulations to investigate the phase diagram of identical hard rhombi systems in two-dimensions. The rhombi's shape varies from nearly square-like, as their minor angle a approaches 90°, to needle-like, as it approaches 0°. For angles near 90°, we get an isotropic fluid, a rhombatic fluid, a rotator phase, and a columnar space-filling structure with increasing density. Conversely, as a approaches 0°, the results resemble the needle limit. Even for angles as small as a = 20°, we still obtain isotropic, nematic, and rhombatic fluids before reaching a rhombic solid, but the nematic phase gains importance with decreasing a. At a ≈ 60°, aperiodic space-filling structures with long-range six-fold orientational symmetry dominate over periodic candidates such as the rhombic and rhombille. This aperiodic solid undergoes a melting process leading to a phase with quasi-long-range six-fold orientational symmetry, a hexatic fluid, before reaching the isotropic phase. [Display omitted] • The phase diagram includes three solid phases: rhombic, aperiodic, and rotator. • It includes four liquid phases: isotropic, nematic, hexatic, and rhombic. • The hexatic phase is completely analogous to the nematic phase. • The aperiodic solid appears for rhombi with a minor angle of 60°. • There are three-step melting pathways. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesized new tolane-LC diluters terminated by the buty-3-enyl or allyloxy group with a simple synthetic route. • Target compound possesses high Δ n , low melting point, low γ 1 and broad nematic phase range at the same time. • LC diluters achieve a fine balance of excellent properties of high birefringence LC mixtures. • DFT calculations of molecular configuration, dipole moment and polarizability were in line with the experimental results. High birefringence (Δ n) and low melting point (T m), high Δ n and low rotational viscosity (γ 1) are two pairs of contradictory performance parameters. In this work, two high-Δ n LC diluters 3PTPF2V and 3PTPFOV are proposed to achieve a fine balance between them. These target compounds containing a rigid tolane core, a lateral fluorine substituent and a buty-3-enyl or allyloxy terminal group were further synthesized. Some experimental instruments, such as POM, DSC, Abbe refractometer, multi-channel liquid crystal evaluation system, were adopted to investigate their properties of mesomorphic phase behavior, T m , Δ n and γ 1 by comparing with classical LC diluters 3HHV and V2PTP2V. Meanwhile, density functional theory (DFT) calculations were employed to correlate the experimental results, and their comprehensive effects on two high-Δ n LC mixtures were further evaluated. Research results indicated that both target compounds possess low T m (∼20 °C), low γ 1 (∼6.5 mPa·s), and high Δ n (>0.26). Performance in high-Δ n LC mixture demonstrated that they could effectively decrease T m and γ 1 , meanwhile maintain high Δ n and T c values, meaning their potential application prospects in fast-response LC optical devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Doping effect of functionalized CdSe/ZnS QDs on the characteristics of 8OCB LC was investigated. • Mobility of ions and diffusion constant were analyzed by a model based on the electrode polarization phenomenon. • Addition of QDs improved ion transport behavior by decreasing the electrode polarization relaxation time. • The threshold voltage drops remarkably with increasing QDs concentration in the LC system. • When the applied field is turned off, the doped samples exhibit a residual transmittance. The current advancements in developing new liquid crystalline materials for the next generation applications focus mainly on improving the physical characteristics of the liquid crystal (LC) systems. Recent progress has shown that the functionalized nanoparticles embedded in LC matrices can significantly alter the characteristics of the LC material based on the mutual interaction between the host molecules and guest particles. In this aspect, the present study reports the impact of dispersing core-shell type CdSe/ZnS quantum dots (QDs) on the dielectric, electrical and electro-optical properties of the 8OCB LC doped at various concentrations. The doped samples exhibit an ion releasing behavior and this effect becomes more evident as the doping concentration increases up to 0.2 wt% in the LC system. It is explained as a result of the growing tactoid-like ellipsoidal form acquired by QDs owing to the enhanced mutual interaction among QD ligands and rod-like LC molecules. The temperature variation of the diffusion constant, conductivity, ionic mobility and mean relaxation time of ions significantly follows each other in all the studied samples. Moreover, thermal profiles of the dielectric anisotropy, threshold voltage and splay elastic constant show a decreasing pattern with an increment in doping concentration. A dual-relaxation regime is experimentally investigated, corresponding to the contribution of nematic director and dimers, providing two kinds of rotational viscosity in the pristine and QDs dispersed LC samples. The transmittance-voltage curve reveals the presence of residual value in the dispersed samples and is related to the volatile memory effect. A slight enhancement is observed in the photoluminescence intensity for the lower doped sample and reduces further with increasing doping concentration in the pristine LC system. All these findings suggest the considerable contribution of functionalized QDs to the studied properties in terms of interaction between the LC and dopant material. This study will further elucidate the selection of optimal QDs concentration based on the required properties for their potential applications in futuristic devices based on LCs. [ABSTRACT FROM AUTHOR]

The heavy fraction (P-A) and the medium fraction (P-B) of coal tar pitch (CTP) were independently hydrogenated by tetrahydronaphthalene (THN) and then blended with the light fraction (P-C) of CTP to obtain modified pitches, from which a fully developed mesophase was prepared. The polycondensation behavior of the hydrogenated fractions and their influence on modified pitches forming mesophase were investigated. The results showed that after P-A fraction was hydrogenated by 10–40 wt% of THN, the H/C atomic ratio increased from 0.57 to 0.59–0.65, precisely as the content of naphthenic structures increased with the condensation index increasing from 0.488 to 0.568. For the hydrogenated P-B, when the ratio of THN increased from 5 wt% to 15 wt%, the alkyl side chains tended to shorten and then grow with their average chain length parameter L decreasing from 3.95 of P-B to 3.81 and then increasing to 4.46. The content of mesophase prepared from modified pitch ranged from 64.33% to 85.65%, in consequence of obvious synergistic effect of the hydrogenated P-A and P-B. Benefiting from the similar condensation degree and average chain length between hydrogenated P-A and P-B, the mesophase content of modified pitches reached 85.65%, including 75.96% of the fiber and flaky textures. The polycondensation reaction between fractions with similar molecular structure proceeds uniformly and smoothly in a well-flowing pitch matrix, resulting in a high content of wide-area mesophase ultimately, which can lay the foundation for the subsequent preparation of high-performance carbon materials. [Display omitted] • Coal tar pitch was hydrogenated in groups to prevent uneven hydrogenation. • Mesophase with content of 85.65% was prepared from modified pitch. • Similar molecular structure between fractions promotes flaky texture mesophase. • Long alkyl side chains result in fiber texture of mesophase. [ABSTRACT FROM AUTHOR]

[Display omitted] • A confined assembly strategy is reported for polarized structural coloration. • DCP is adjusted by kinetic trapping multi-domain cholesteric mesophases. • The chiral photonic materials can be applied for information storage and encryption. Chiroptical materials with tunable circular polarization performances have gained wide interest because of promising applications in optical devices and information communication. However, limited by their intrinsic chirality, such materials suffer from serious deficiencies in dynamical manipulation on circularly polarized light (CPL). Here, we demonstrate a kinetic trapping approach to capture multi-domain cholesteric mesophases for polarization-dependent structural coloration. The resultant photonic structures depicted by limited solvent evaporation display light control from selective left-handed circularly polarized light reflection to dual reflection, as a result of forming highly tilted and distorted domains with a phase-retardation effect. Notably, a positive linear correlation is established between the circular polarization behavior and structural orientation regulated by the solvent evaporation. The tunable circular polarization structural colors enable the application of the photonic materials for complex encryption in terms of polychromatic coding arrays. The confined-anisotropic-fabrication method of photonic structures paves a foundation toward advanced functional materials with promising applications in light science and technology. [ABSTRACT FROM AUTHOR]

Incorporating supramolecular chirality and high emission into metallomesogens has great significance in the field of flexible electronic devices because of their emergent capacities for enlarged chiroptical activities and either thermotropic or solution-processability. In this work, an enantiomeric pair of chiral Pt(II) metallomesogens (S)/(R)-Pt1 were prepared through laboratory-synthesized chiral picolinic acid ligands and phenylpyridine derivatives to study their mesophase behaviors, chiroptical properties, and chirality transfer and amplification. The solutions of (S)/(R)-Pt1 emitted green phosphorescence at 508 nm, but the amorphous form displayed orange-red phosphorescence at 616 nm. Upon gentle grinding or heating, the emission color of Pt1 was dramatically changed with a bathochromic shift of 47 and 51 nm, respectively, because of emerged intermolecular π···π and Pt ⋯ Pt interactions in all aggregation states. Furthermore, the chiroptical properties and LC self-assembly model were proposed by Density Functional Theory (DFT) calculations and chiroptical spectrum measurements. The enantiotopic (S)/(R)-Pt1 complexes exhibited electronic circular dichroism (CD) and circularly polarized luminescence (CPL) activities in solution with a smaller asymmetry factor (±5 × 10−4) by chiral disturbance. This pair of exclusively enantiomeric complexes exhibited smectic mesophase behavior in the range of 31.4–76.5 °C but induced unsuccessfulness of helical packing in LC states due to weak induction ability. Contrastively, binary-component mediated supramolecular helical formation and amplificated deep-red CPL switch with ultrahigh dissymmetry factor over ±0.13 in helical twist grain boundary phases (TGBA*) mesophase has been realized. [Display omitted] • A pair of chiral cycloplatinated(II) metallomesogens showed phase-dependent chiroptical properties • Effective binary-component mediated supramolecular chiral assembly and amplification. • Deep-red CPL with ultrahigh dissymmetry factor over ±0.13. • Pt(II) metallomesogens can serve as janus role of LC host and emitter. [ABSTRACT FROM AUTHOR]

[Display omitted] • Re-entrant behaviours, which were rarely reported for pure matters of dimeric liquid crystals, were analyzed. • Relaxation effects play an important role during the cooling process from a SmA* phase to a TGB phase. • An abnormal phase transition of TGBC*-SmA* was analyzed. • The selective reflection wavelength of re-entrant TGBA blue shifts to the visible light range by doping method. • This series of dimers are compared with other series to study the structure–property relationship. Re-entrant mesophase behaviours are studied including the relaxation effect of TGB phases, and an abnormal phase transition of TGBC*-SmA*. For the re-entrant TGBA mesophase between SmA* and TGBC*, its temperature range can be expanded by doping method and meanwhile its selective reflection wavelength moves to the visible light range. Furthermore, this series of dimers are compared with other series to study the structure–property relationship. This research provides an important reference for preparing materials exhibiting multiple mesophases that reflect visible light within multiple temperature ranges. [ABSTRACT FROM AUTHOR]

• Odd-even effect in the Cholesteric PBG in equilibrium and photoinduced state. • Memory effect in 2D PBG of TGBC* phase. • Actinic light and spacer parity control on PBG in 3-dimension. We describe the first investigations on the influence of flexible spacer parity of the guest photoactive liquid-crystalline dimer on the photonic bandgap (PBG) features of the cholesteric (Ch) and twist grain boundary smectic C* (TGBC*) phases of the host molecule. Both these phases exhibit PBG structure, with the former having it in one and the latter in three dimensions respectively. The concentration of the photoactive dimer is very small in the host liquid crystal (HLC) system that exhibits isotropic (Iso) → Ch → TGBC* sequence. The photoisomerization experiment brings out the feature that the pitch of the Ch phase blue-shifts, with the magnitude being more for the even dimer system compared to the odd one. This effect is accompanied by a reduction in the width of the photonic bandgap, again the effect is more pronounced for the even parity mixture compared to the odd one. The two-dimensional periodicity of the SmC* helix identified with the grid pattern in the TGBC* phase shows the memory effect upon photoisomerization. X-ray diffraction measurements reveal that the odd dimer system shows a larger layer spacing than the even dimer one. Upon UV illumination for one of the materials, layer spacing shows an increase. The investigations discussed in this article reveal that, apart from the actinic light, the spacer and parity of the photoactive dimer play a significant role in controlling the PBG properties in all three directions. [ABSTRACT FROM AUTHOR]

• A novel separation and screening process for petroleum pitch is demonstrated. • This method employs the high pressure CO 2 extraction and anti-solvent process. • A novel GPC analysis system with dual UV and RI detectors is developed. • A novel high pressure CO 2 anti-solvent apparatus is applied in this study. • The raw pitch is successfully separated with good polyaromaticity index. Mesophase pitch, as an important chemical intermediate, belongs to highly structured pitch materials that has good property for conducting heat or electricity. Pitch can be naturally derived from petroleum or coal tar. Prior to producing the mesophase pitch materials, the removal of complex low molecular weight polycyclic aromatic hydrocarbons (PAHs) from the original petroleum pitch is essential. In the study, we have developed a two-step process using high pressure CO 2 for separating the useful part with desired properties from the raw petroleum pitch sample. Firstly, a stepwise supercritical CO 2 (scCO 2) extraction process was employed for removing the lightest molecular weight fractions. The residual and CO 2 -insoluble fractions were further separated by a subcritical anti-solvent (SAS) process using CO 2 at 25 °C and three high pressure conditions. A modified SAS apparatus was utilized in this study. The gel-permeation chromatography (GPC) analysis system with standard calibrations was used to determine the molecular weight of various pitch samples. The GPC system was equipped with dual Ultraviolet (UV) and Refractive Index (RI) detectors. The polydispersity index (PDI) value of the raw petroleum pitch 6 (PP6) sample was 6.9, and it was reduced to 3.8 after the scCO 2 extraction and under the appropriate SAS processing pressure. The corresponding weight average molecular weight (M w) was increased from 987 to 1493 g/mol. This study provides an effective separation and product identification method that only employs commonly used GPC analyses with dual UV and RI detectors. A useful screening method has been developed for selecting the most appropriate separation parameters. [ABSTRACT FROM AUTHOR]

Two series of 4,6-diamino-1,3,5-triazine triblock polyphiles consisting of an extremely long bisthiophene/triazole based rigid cores, with flexible alkyl chains at one end and a polar 4,6-diamino-1,3,5-triazine at the other end were synthesized. Col hex / p 6 mm mesophases were displayed by all bisthiophene based 4,6-diamino-1,3,5-triazine derivatives, whereas both Col hex / p 6 mm and Cub I / Pm 3 ¯ n mesophases could be formed by corresponding triazole based 4,6-diamino-1,3,5-triazine derivatives. Evidence for the formation of the extra H-bonding between central triazole units and terminal 4,6-diaminotriazine groups which was responsible for the formation of cubic phases in triazole based compounds was obtained based on FT-IR measurements. Additionally, these triblock polyphiles can form organogels with interesting morphologies in different solvents. The influence of the alkyl chain length and the polarities of the heterocycles (bisthiophene/triazole) on the self-assembly of these compounds was systematically studied. Finally, these triblock polyphiles showed dual selectivities towards Pb2+ and Fe3+ ions. Image 1 • Bisthiophene/triazole diamino triazine triblock polyphiles have been synthesized. • They display Col hex / p 6 mm and Cub I / Pm 3 ¯ n mesophases despite their long rigid cores. • These compounds can form organogels in organic solvents with different morphologies. • These compounds can act as chemosensor of metal ions. [ABSTRACT FROM AUTHOR]

• The growth of a one-dimensional silica network in the confinement of the reverse microemulsions led to gel formation. • Two kinds of the gels were prepared by adding different amounts of TEOS within the water to organic solutions of different AOT concentrations. • The size of silica nanowires can be tuned by the change of TEOS concentrations. Self-assembled hybrid gels were formed by adding amounts of tetraethyl orthosilicate (TEOS) dissolved in water to organic solutions of sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol-OT, AOT). Two kinds of hybrid gels were prepared and discussed in this study. In the first, gels were prepared through chemical hydrolysis-condensation reactions of TEOS. The growth of a one-dimensional silica network in the confinement of the AOT reverse microemulsions led to gel formation. In the other, gels were prepared through reverse hexagonal mesophases due to high concentrations of AOT. Rheological studies demonstrated that the elastic modulus, G' , is greater than the viscous modulus, G" , at all frequencies, and G' did not depend upon the frequency in either system, implying they can be used as gels. The gels obtained through silica networks had smaller G' values and higher transformation strains than those gels prepared through AOT reverse hexagonal mesophases. Small-angle X-ray scattering (SAXS) results showed that both systems exhibited cylindrical structures with short-range order, and the radii of the cylinders were significantly influenced by the change of AOT, TEOS and water concentrations. Transmission electron microscopy (TEM) confirmed that silica nanowires were found in both gel systems after removing the AOT components. The length of the nanowires for the gels prepared through silica networks was larger than that for the gels prepared through AOT reverse hexagonal mesophases. This was because the silica grew into a one-dimensional network (axial direction) due to the confinement of the cylindrical structures. Size-tunable silica nanowires prepared using reverse microemulsion-gel systems. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • In this paper, the mesophase pitch with wide-area streamlined texture were obtained. • The additive can significantly promote the formation of mesophase spheres. • The additive can shorten the time required for the formation of mesophase pitch. Abstract By adding naphthalene-based mesophase pitch (NBMP) into refined coal tar pitch (RCTP), pyrolysis products were obtained by dry-blending and co-carbonization method. The properties of pyrolysis products were characterized by polarizing microscope, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD) and Raman spectroscopy. The result shows the NBMP can obviously change the mesophase development of RCTP because it can promote the formation of mesophase spheres during the pyrolysis process. The carbon yield and aromaticity of pyrolysis products were increased with the increase of NBMP content. The anisotropic texture was wide-area structure when the NBMP content was 5 wt%. However, when the content of the additive is increased to 10 wt%, pyrolysis products will appear coking. The main role of this additive is to accelerate the reaction rate as the "nucleating agent" of the thermal condensation reaction. [ABSTRACT FROM AUTHOR]

Abstract Herein, the synthesis of mesoporous organosilica nanoparticles with cubic and dodecagonal quasicrystalline mesophases is reported. Mesoporous nanoparticles are synthesized by base-catalyzed hydrolysis and condensation reactions of silane-based monomers in the presence of hexadecyltrimethylammonium bromide (CTAB), which is used as a structure-directing agent to form the mesostructures. Cubic orders in the mesophases are formed using tetraethoxysilane monomers, and the mesophase is tuned to the dodecagonal quasicrystalline order by using binary monomers including tetraethoxysilane and dimethyldiethoxysilane. The size of the quasicrystalline-phase organosilica is tailored by changing the amount of base catalyst used. Additionally, we obtained well-defined core/shell structures with quasicrystalline ordered mesoporous organosilica. Furthermore, we investigate the cytotoxicity of mesoporous organisilica nanoparticles using a CCK-8 assay to demonstrate that our NPs have a potential for the utilization as biomedical applications. These novel findings could guide the formation of mesophase structures with quasicrystalline order in silica-based mesoporous nanoparticles. Graphical abstract Unlabelled Image Highlights • A mesoporous organosilica nanoparticle with cubic and dodecagonal quasicrystalline orders is successfully synthesized via a sol-gel reaction using CTAB as a template. • Cubic orders in the mesophases are formed using TEOS and the mesophase is tuned to the dodecagonal quasicrystalline order by using TEOS and DMDES co-monomers. • The inorganic-mesoporous organosilica core/shell structures are synthesized with quasicrystalline mesophases. [ABSTRACT FROM AUTHOR]

Graphical abstract A schematic illustration of the formation of spherical and hexagonally arranged rod-like micelles at different concentrations of CTAB. Highlights • Electrodeposition of mesoporous films from micellar CTAB cationic surfactant. • Meso-porous structures from disordered to hexagonally ordered pores. • Significant effect of CTAB concentration and deposition current density. • First-order reversal curve (FORC) diagrams reveal structure-magnetic properties relationship. Abstract Mesoporous magnetic materials have found interesting potential applications in electrochemical energy harvesting and energy-efficient magnetic actuation device applications. Here we report on the electrodeposition and magnetic properties of mesoporous nickel films from lyotropic liquid crystal (LLC) templates formed by cetyltrimethylammoniumbromide (CTAB) cationic surfactant. Diffusion-controlled electrodeposition mechanism of nickel is determined. Films are electrodeposited under a constant current ranging from 1 to 7.5 mA cm−2 from an aqueous solution containing 0.1 M nickel sulphate, 0.2 M boric acid solution and CTAB with a concentration ranging from 0 to 50 wt.%. Mesopores develop an arranged hexagonal structure due to the micellar positional and orientational order reaching its highest value at 30 wt.% of CTAB at 2 mA cm−2. This is confirmed by transmission electron microscopy (TEM) and electrocatalytic surface area measurement. Electrodeposition current density and pH modify the mesoporous dimensions and therefore the magnetic properties change, tough hydrogen evolution as a side reaction influences the mesoporous structure. We observe an increased in-plane magnetic coercivity value to a maximum of 214 Oe for the mesoporous nickel film, which correlates with the increased interaction field. The widening of the coercivity distribution in first-order reversal curve (FORC) diagrams indicates that films with higher CTAB content have more inhomogeneous structure, which can lead to complex magnetization reversal mechanisms. The results of this study will help to exploit novel multifunctional magnetic and electrochemical energy materials and devices. [ABSTRACT FROM AUTHOR]

Abstract Fluid phase behaviour of three isomeric 1,3,6-trisubstituted benzo[ e ][1,2,4]triazin-4-yl derivatives with the half-disc molecular architecture was examined in the pure form and in binary mixtures. Results indicate that the position of substitution with two wedge-shaped 3,4,5-tridodecyloxyphenyl groups and one Ph group has dramatic impact on the Col h phase stability, which ranges from 73 °C to presumably below −60 °C. Analysis of electronic and steric factors suggests that the intermolecular interactions of the wedge-shaped substituents are dominant and through their conformational behaviour they affect packing of the column's core and hence phase stability. Graphical abstract Unlabelled Image Highlights • Isomeric disc-like derivatives of a stable radical with diverse mesophase behavior • Columnar phase binary mixture investigation • Correlation of DFT-derived structural parameters with mesophase behavior. [ABSTRACT FROM AUTHOR]

Abstract The first mesomorphic benzimidazolium based mononuclear silver (I) N -heterocyclic dicarbene complexes, Ag(I)-NHC were prepared via in situ deprotonation of 1-octadecyl-3-alkyl/arylbenzimidazolium salts with silver oxide (Ag 2 O). Both series of Ag (I)-NHC complexes contained a C18 alkyl chain on one N atom and differed in term of the substituent (alkyl and substituted benzyl moiety) on the other N atom in the benzimidazolium ring. All the synthesized compounds were characterized by elemental analysis, Fourier-transform infrared, 1H and 13C NMR spectroscopy. Cation geometry, anion and alkyl chain length were found to be essential parameters for mesophase formation in the salts and Ag(I)-NHC complexes in this study. All dialkylated salts except the one with the shortest chain, n = 10 were smectogenic. On the other hand, a large width-to-length ratio of the cationic core in the benzyl analogues had a negative effect on the formation and stability of mesophase. No mesophases were observed for these compounds. Wider mesophase range was seen with decrease in anion size and elongation of alkyl chains. A metastable SmA phase was observed in two Ag(I)-NHC complexes. The minimum chain length required for compounds with different anions to exhibit liquid crystal (LC) properties was addressed. Mesophase was observed for bromide salts with C12 onwards while C14 is the minimum chain length required for the hexaflurophosphate containing Ag(I)-NHC complexes to display LC properties. All Ag(I)-NHC complexes except the one bearing a cyano group could be considered ionic liquids with melting/clearing temperatures below 100 °C. Graphical abstract Unlabelled Image Highlights • The first mesomorphic benzimidazolium based complexes, Ag(I)-NHC were prepared. • The relation between chemical structures and mesomorphic behaviour was established. • The minimum chain length required for mesomorphic behaviour was addressed. • Most of the synthesized Ag(I)-NHC has melting/clearing temperatures below 100 °C. [ABSTRACT FROM AUTHOR]

Abstract In this study, the dielectric properties of the liquid crystal 4–(7,7,8,8,9,9,10,10,10–nonafluorodecyloxy)biphenyl–4′–carboxylic acid (NBCA) exhibiting a Smectic C mesophase have been analyzed. NBCA has two critical temperatures which are 194 °C for the crystal phase to the smectic phase transition, and 269 °C for the smectic phase to the isotropic phase transition. Impedance spectroscopy measurements were made at regular intervals at different temperatures which includes these transitions. By using capacitance method, the complex dielectric constants have been calculated for each temperature, and the real part of dielectric constants have been fitted to the Cole-Cole equation. In addition, ac conductivity mechanisms of the NBCA at different temperatures and different phases and also activation energies which belongs to some selected frequencies have been determined by the imaginary part of dielectric constants. Highlights • The dielectric properties of the liquid crystal NBCA have been analyzed. • The transition temperatures were verified by dielectric measurements of the NBCA. • The conductivity mechanisms for different temperatures have been determined. • The activation energies for selected angular frequencies have also been calculated. • This characterization of NBCA can be beneficial for liquid crystal applications. [ABSTRACT FROM AUTHOR]

Abstract Mesocarbon microbeads (MCMBs) are a valuable carbon material, and the production of this material highly depends on the reaction conditions and feedstock properties. In the present study, supercritical fluid extraction fractionation (SFEF) technology was used to separate coal tar pitch (CTP) into a series of fractions to enhance MCMB preparation. After SFEF separation, most of the toluene-insoluble (TI) components were concentrated into the unextracted residue. First, optimal carbonization conditions were obtained for CTP through systematic experimental evaluations. Then, the SFEF fractions were heat-treated under the optimal conditions to produce MCMBs, and the relationship between chemical composition and product quality was revealed. Compared with CTP products, MCMBs produced from extracted SFEF fractions showed better morphology, and only a bulk mesophase with poor texture was generated from the unextractable residue. Moreover, the TI fraction had a significant negative impact on MCMB production in carbonaceous mesophase development. The results indicate that supercritical fluid extraction can be used to improve the quality of produced MCMBs by removing undesirable components. [ABSTRACT FROM AUTHOR]

Abstract A new series of photosensitive azo materials possessing a chiral alkyl lactate moiety and terminal n-alkyl carboxylate unit close to the azo group has been synthesized and studied. The length of the n-alkyl carboxylate chain has been systematically varied in order to establish the effect of the molecular structure on the self-assembling behaviour. Two series of materials possessing hexyl and dodecyl alkyl chains in the chiral part of the molecule have been studied. It has been shown that the length of both the alkyl chains strongly influences the mesomorphic behaviour, however, each chiral/achiral chain has different utility to tune the mesomorphic properties. With exception of the compound with the longest chains, all studied compounds exhibited the chiral tilted ferroelectric smectic C* phase. Based on the combination of terminal alkyl chains, chiral nematic, orthogonal smectic A*, and twist grain boundary smectic A* phases have been detected on cooling beyond the SmC* phase. The presence of the photosensitive functional N=N group in the molecular core allowed further tuning of the material properties by UV light illumination. The E -to- Z photoisomerization of the azo group and subsequent thermal back-isomerisation have been studied in solution by nuclear magnetic resonance and most importantly in the mesophases on bulk samples. We report on UV-induced isothermal switching from chiral smectic and nematic mesophases into the isotropic phase, respectively, and differences in the textures of mesophase upon restoration of the ordered liquid. Highlights • Photosensitive chiral liquid crystals exhibiting a broad SmC* phase as well as SmA*, TGBA* and N* phases are presented. • Low-energy UV light induces isothermal phase transition from SmC* over TGBA* (SmA*) and N* phases into the isotropic phase. • Fast isothermal transition from any mesophase to isotropic phase is enabled by high-energy UV light. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Tea three based-formulations showed bioadhesive in the skin surface. • in vivo repellent activity against the Aedes aegypti mosquitoes were achieved. • Cubic mesophase showed better results on in vivo repellent activity. • Viscosity plays a role on in vivo repellent activity. Abstract Diseases such as dengue, malaria, yellow fever and others transmitted by culicides determine high rates of morbidity and mortality, especially in tropical countries. An alternative to avoid bites is the use of repellents. The most commonly used is DEET (N, N-diethyl-3- m -toluamide) repellent, but there are reports describing cases of toxicity with misuse or long-term use. Due to these disadvantages many people prefer to use natural products for repellents purposes. Studies have shown that different essential oils have repellent activity, but research should be conducted in order to obtain formulations that are effective in fixing aromatic compounds on the skin and increasing the duration of repellency. Nanostructured systems for the incorporation of natural active principles, such as liquid-crystalline systems (LCS), have advantages in solubilization of compounds, increase stability and effectiveness of them. Four formulations composed of water, hydrogenated castor oil PEG-40, as surfactant, and melaleuca essential oil, as oily phase, were prepared and characterized by polarized light microscopy, rheological, mechanical and bioadhesive behavior. Their in vivo repellent activity against the Aedes aegypti mosquitoes was determined. Presence of cubic liquid-crystalline mesophase regions and microemulsions were confirmed by polarized microscopy. The rheology tests showed that the fluids are non-Newtonian like pseudoplastics fluid and they have elastic characteristics. The bioadhesion assay showed that the cubic mesophase formulations are more bioadhesive than the microemulsions. Formulations showed repellency against A. aegypti. The results show the repellent activity of nanoestructured systems based on essential oil of melaleuca and prospects for the development of new and innovative formulations based natural products. [ABSTRACT FROM AUTHOR]

Abstract Charred/devolatilized megasporinite and featureless vitrinite with devolatilization pores filled with pyrolytic carbon suggest that eastern Pennsylvania anthracites may have been altered by to localized episodes of metamorphism from superheated steam/CO 2 /CO/hydrocarbons, in addition to the pervasive regional metamorphism. Based on the extant vitrinite textures, the lack of mesophase anisotropic textures, and on comparisons to laboratory studies of the thermoplasticity of bituminous coals, the rank at the time of metamorphism would have been high volatile C or lowermost high volatile B bituminous. The temperature of alteration would have been in the 350–400 °C range, corresponding to the critical point of steam (374.15 °C and 22.1 MPa; about 1-km depth). It is speculated that while increased pressure would have prolonged the duration of fluid properties, fluidity is still a transient property and the vitrinite would have returned to a solid state after a few hours. The heat would have persisted, dissipating over the course of days to months to years depending upon the depth and ambient (pre-heating) geothermal gradient, but contributing to the coal metamorphism long after the vitroplast solidified. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the investigation of a donor-acceptor copolymer of 3-hexylthiophene and benzothiadiazole (PDHTBT) to generate macroscopically oriented nanofibers by self-assembly approach to be used as an active layer for organic field effect transistor (OFET). Aligned polymeric nanofibers with long range order was confirmed by various microscopic techniques and XRD analyses. OFET containing aligned nanofibers (Si/SiO 2 /PDHTBT/Ag) exhibited an impressive field effect mobility of 2.29 ± 0.85 cm2/V.s with an ON/OFF ratio of ∼105 and a low threshold voltage of −0.47 ± 0.05 V at room temperature which relies on the texture and domains generated in the film. Light induced enhancement in charge transport owing to the formation of photo-induced charge carriers postures a facile strategy for the fabrication of high performing plastic electronic devices. Graphical abstract Image 1 Highlights • Aligned PDHTBT as active layer. • Mobility of 2.29 cm2/V.s. • Threshold voltage of −0.47 V [ABSTRACT FROM AUTHOR]

Abstract A class of Zn(II) polymethacrylate mesogen was tailored with photoluminescent property as well as high thermal stability by wrapping the Zn(II) metal in polymethacrylate mesogenic core. The versatile thermal stability of the mesophase was accounted by long chain terminal alkoxy groups and jacketed Zn(II) metal core. The extended stable mesophase with rise in temperature was achieved by excellent coordination between the supramolecular ligand with that of metal core. The Schiff base was prepared by treating (1-bromo (4-dodecyloxy azobenzene)) with octadecyl amine in ethanolic medium. The Schiff base obtained was polymerised with methacrylic acid (MA) in presence of AIBN as free radical initiator. The supramolecular mesogenic ligand (PMA-L) was further complexed with Zn(II) acetate in 1:1 M ratio. The Zn(II) supramolecular mesogen was extensively characterized by 1H NMR, 13C NMR and FT-IR. The mesomorphic behaviour was studied by XRD diffractogram, DSC, POM. The Zn(II) supramolecular exhibits columnar phase transition due the molecular stacking in disc shape. The disc shape mesophase of the Zn(II) supramolecular mesogen was achieved by sandwich pattern of metal core between two organic ligands arrangement. The photo physical character of the Zn(II)polymeric mesogen was studied by absorption and fluorescence spectral method. Graphical abstract Unlabelled Image Highlights • Photo luminescent supramolecular Zn metallomesogens was synthesized. • Zn mesogen exhibits intense emission band at 364 nm at room temperature. • Highly utilizable for ultra light electro optical devices • High thermal stability due intra-ligand bonding and hydrogen bonding network • Clearly produce columnar hexagonal phase transition with high stability [ABSTRACT FROM AUTHOR]

Highlights • A new kind of diffraction patterns of hexagonal was observed in the matrix of C/C composite. • The graphite nanocrystals with different orientation existed in the matrix. • The possible located relationship between main graphite and nanocrystallines was discussed. Abstract Mesophase pitch-based C/C composite is one of the best candidate materials for high thermal conductivity. In this work, the fine microstructure of its matrix has been analyzed by high-resolution transmission electron microscopy (HRTEM). Interestingly, although the results show that the matrix is composed of hexagonal graphite, the [11–20] and [10–10] zone axes coexist in the same pattern (at variance with traditional diffraction theory). Furthermore, a large number of differently oriented nanostructures interwoven with the main hexagonal graphite have been identified by a series of tilting diffraction patterns, dark-field images, and high-resolution TEM images. The relative positional relationship between these nanostructures and the main graphite has been obtained. This paper provides a theoretical basis for the improvement of thermal conductivity and other properties (such as Li+ and Na+ storage) of mesophase pitch-based C/C composites. [ABSTRACT FROM AUTHOR]

Abstract Herein, we have reported the alkyl and alkoxy phenylacetylene containing phenazine fused triphenylene discotic liquid crystals (DLCs) which are obtained by the condensation reaction of triphenylene-1,2-diquinone with 1,2-diamino-4,5-dibromobenzene, followed by Sonogashira C–C coupling reaction with 4-alkyl-phenylacetylene or 4-alkoxy-phenylacetylene. Six novel derivatives were synthesized and evaluated for their thermal and optical properties. They show a broad range of hexagonal columnar phase and retain their mesophase up to room temperature upon cooling from the isotropic liquid. Thermotropic liquid crystalline properties of all the compounds were studied by polarised optical microscopy (POM), differential scanning calorimetry (DSC). The self-assembly of mesophase structure was investigated by X-ray diffraction (XRD) studies. Thermogravimetric analysis of all the mesogens shows good thermal stability over a broad temperature range. The photophysical properties of newly synthesized compounds were measured using UV–Vis absorption and photoluminescence emission spectroscopy in anhydrous chloroform solvent. The π-extended conjugation in these mesogens exhibit strong absorption bands falling around 270–487 nm and corresponding emission band at 657–663 nm respectively. The high delocalization of π– electrons in extended discotic mesogens show high nonlinear optical properties when measured under excitation by nanosecond laser pulses at 532 nm. These materials may find distinctive applications in the semiconducting devices. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract Four new groups of Schiff base ester liquid crystal compounds, 4-(arylideneamino)phenyl-4″-alkoxy benzoates, I n a – d , were prepared and investigated for their mesophase formation and stability. An alkoxy group of variable chain length (n = 6, and 16 carbons) is attached to the terminal phenylazo benzoate moiety. Each group constitutes two homologous series that differ from each other by the polar substituent X (CH 3 O, H, NO 2 , and F). The molecular structure of the prepared compounds was confirmed via FT-IR, 1H NMR, mass spectroscopy and elemental analysis. The mesomorphic properties were investigated by differential scanning calorimetry (DSC) and polarized light microscopy (PLM). For n = 6, all compounds exhibit nematic phase. Amongst them methoxy and nitro derivatives have widest mesophase range. For n = 16, nitro and flouro derivatives exhibit SmA phase, while methoxy and unsubstituted derivative are nematogenic. The change of the mesophase stability is well correlated with van der Waals volume and polarizability of the substituent X and not satisfactory with the dipole moment of the whole molecule. The mesophase behavior of binary mixtures made from each individual derivatives bearing the same substituent X but varies with alkoxy chains length is presented. Results provide insights into the role of substituent X and alkoxy chain length on the mesophase behavior within the whole composition range of the mixtures. Highlights • New Schiff base ester liquid crystals were prepared. • Mesomorphic properties were investigated by DSC and PLM. • All Schiff base esters were enantiotropicmesomorphic with high stability ranges. • Theoretical studies revealed that the stability dependent on the terminal group X. • The substituent X affects the energy difference between FMOs (NO 2 < H < OCH 3 < F). [ABSTRACT FROM AUTHOR]

• (1S)-camphanic-decorated biscyanostilbene was prepared and exhibited two conformers. • Its Sm phase in cis -like conformer emitted right-handed CPL with a g lum of −0.019. • Its suspension in trans -like conformer exhibited left-handed CPL with a g lum of 0.018. • The inversion of CPL based on assemblies in mesophase and suspension was developed for the first time. The regulation of circularly polarized luminescence (CPL) signal is of great significance for practical application but rarely reported. In this work, the sign inversion of CPL based on assemblies in smectic mesophase and suspension was developed. Two stable conformers of (1S)-camphanic-decorated biscyanostilbene accounted for the formation of two different helical superstructures. Smectic mesophase was found to be a bilayer structure consisted of cis -like conformer and emitted right-handed CPL with a g lum of −0.019, while chiral assembly in suspension was made up of trans -like conformer and exhibited left-handed CPL with a g lum of 0.018. This research supplied a new strategy to tune the inverted CPL signal of homogeneous organic molecular system by simple external condition control. [ABSTRACT FROM AUTHOR]

[Display omitted] Liquid crystal (LC)-based nanoformulations may efficiently deliver drugs and therapeutics to targeted biological sites. Lyotropic liquid crystalline phases (LLCPs) have received much interest in recent years due to their unique structural characteristics of both isotropic liquids and crystalline solids. These LLCPs can be utilized as promising drug delivery systems to deliver drugs, proteins, peptides and vaccines because of their improved drug loading, stabilization, and controlled drug release. The effects of molecule shape, microsegregation, and chirality are very important in the formation of liquid crystalline phases (LCPs). Homogenization of self-assembled amphiphilic lipids, water and stabilizers produces LLCPs with different types of mesophases, bicontinuous cubic (cubosomes) and inverse hexagonal (hexosomes). Moreover, many studies have also shown higher bioadhesivity and biocompatibility of LCs due to their structural resemblance to biological membranes, thus making them more efficient for targeted drug delivery. In this review, an outline of the engineering aspects of LLCPs and polymer-based LLCPs is summarized. Moreover, it covers parenteral, oral, transdermal delivery and medical imaging of LC in targeting various tissues and is discussed with a scope to design more efficient next-generation novel nanosystems. In addition, a detailed overview of advanced liquid crystal-based drug delivery for vaccines and biomedical applications is reviewed. [ABSTRACT FROM AUTHOR]

A liquid crystalline system formed by rod-shaped molecules that have a small transverse dipole moment is analyzed in the presence of an external electric field normal to the smectic layers. The approach focuses on the phase transition diagram displaying the N–Sm–A-Sm-C phases, when both negative and positive dielectric anisotropies are considered. The analysis is carried out within the framework of an extended mean field theory, which shows the emergence of a re-entrant Sm-C phase in the strong field regime, accompanied by a suppression of the translational ordering of the Sm-A phase, in the case of a negative anisotropy. A different scenario is observed in the case of positive anisotropy, as the electric field tends to suppress the Sm-C phase because the molecular alignment is driven by the field along its direction. In this case, the emergence of a residual nematic phase is also observed, which replaces the isotropic phase and is characterized by a low-value orientational order parameter. • A smectic system of rodlike molecules with a small transverse dipole is studied. • The effects of an electric field on the N-Sm-A-Sm-C phase transitions are considered. • A re-entrant Sm-C phase may be observed, depending on the dielectric anisotropy. • The external field may suppress or reinforce the translational order of Sm-A phase. • The extended microscopic model provides a very rich phase diagram. [ABSTRACT FROM AUTHOR]

The boron trifluoride complex catalyst can effectively facilitate the development of anisotropic structures in FCC decant oil (FCC-DO) through cationic polymerization reaction. However, the fractions of FCC-DO with different boiling points possess different molecular compositions and aromatic nuclei configurations. In this study, FCC-DO is separated into light fraction, middle fraction, and heavy fraction by vacuum distillation. The different carbonization reaction pathways and reactivity were systematically investigated for three narrow fractions with no or 5 wt% addition of boron trifluoride complex catalyst. The results show that the heavy fraction is dominated by 4 and 5 plus ring aromatics with short side chains and methylene-bridged bonds. The catalyst showed excellent catalytic activity for the heavy fraction, the resulting product (MP-HF-5) possessing a softening point of 307 °C and 3.06 wt% methylene-bridged hydrogen at 95.3 wt% mesophase content. However, the catalyst slightly facilitated the development of anisotropic structures in the middle fraction (rich in 3 and 4 rings aromatics with naphthenic structures), which provided mesogen molecules during the FCC-DO carbonization reaction. Finally, the 1 ∼ 3 ring aromatics with long alkyl side chains are mainly present in the light fractions. The catalyst did not show obvious catalytic activity for the light fraction, in contrast, the oxygen-containing functional groups in the catalyst reacted with the aromatic molecule to form a disordered oxidative cross-linked structure, resulting in an almost completely isotropic structure of MP-LF-5. [Display omitted] • Molecular structure determines the reaction path of narrow fractions with boron trifluoride ethyl valerate complex catalyst. • Catalyst shows excellent catalytic activity on heavy fractions and generates more semi-rigid structure. • Catalyst slightly promotes anisotropic phases development in middle fraction generating more mesogens. • Catalyst introduces oxidative cross-linking structure in light fraction disrupting microcrystalline orderliness. [ABSTRACT FROM AUTHOR]

The electro-optical properties of some four-armed liquid crystalline materials with pentaerytrithol core based on coumarin as mesogenic moiety is investigated. The mesogenic moiety is connected to the core via spacers with various chain lengths differing. The compounds are investigated via differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) equiped with a temperature controlled hot-stage. Field-Emission Scanning Electron Microscope (FESEM) and "High-Resolution Transmission Electron Microscope (HRTEM) measurements are exhibited a relatively spherical morphology with particle sizes of 145–174 nm. The electro-optical performance of the materials as thin films coated on indium-tin-oxide (ITO) glass substrates are investigated via applied voltage versus transmittance plots, exhibiting relatively low driving voltage values as low as 2.5–3 V. The ordinary (n o) and extraordinary (n e) refractive indexes of the compounds at different temperatures are measured showing a good correspondence with the POM results. In conclusion, the studied materials have exhibited proper physicochemical and electro-optical properties as materials for liquid crystal displays (LCD). [Display omitted] • Electro-optical properties of pentaerytrithol-coumarin based liquid crystals studied. • Mesogenic moieties connected to core via spacers with various chain lengths. • DSC and temperature dependent n o and n e of compounds corrlated with POM results. • Materials exhibited relatively low driving voltages as low as 2.5 and 3 V. [ABSTRACT FROM AUTHOR]