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A chiral supramolecular liquid crystal based on a pillararene mesogen was constructed. The regulation of liquid crystal behavior was achieved through the host–guest interactions between the pillararene-based mesogen and a tetraphenylethylene-containing guest. In addition, this supramolecular liquid crystal system, showing pH-responsive fluorescence emission character, was applied as an information encryption material capable of storing multiple levels of distinct information, thereby enriching the application of liquid crystal materials in the field of information security. [ABSTRACT FROM AUTHOR]

Novel liquid crystal elastomers (LCEs) with solely Diels–Alder dynamic covalent bonds (DADCBs) as crosslinks and body temperature sensitivity have been developed. The appealing attributes of the material, such as recyclability, reprogrammability and reconfigurability, have led to soft actuators capable of reversible deformation stimulated by shifting between ambient and body temperature, highlighting the potential for innovative applications in the biomedical field. [ABSTRACT FROM AUTHOR]

The document from Chemical Communications, published in 2024, provides a comprehensive list of articles covering various topics in chemistry. It includes research on electrochemical deconstructive functionalization, organoboron catalysis, recent progress in sensing technologies, and advancements in metal carbene-induced rearrangements. The journal aims to uncover new possibilities through original discoveries and fundamental questions in the field of chemistry. [Extracted from the article]

We designed V-shaped ionic liquid crystals with two sterically congested ionic parts at the vertex. Depending on the degree of steric hindrance, atropisomerisation occurred in solution. All compounds formed bicontinuous cubic phases with double-gyroid structures in the bulk state, partially owing to the co-existence of atropisomers with opposite chirality. [ABSTRACT FROM AUTHOR]

Due to their high anisotropic behavior, liquid crystals possess strong nonlinear optical properties. The RM734 liquid crystal is famous for having high anisotropic behaviors compared to traditional liquid crystals. The present work focused on the evaluation of electronic, charge-transport, nonlinear optical, electro-optical, and thermochemical properties of the RM734 liquid crystal. Furthermore, the effect of halogenation on the above properties of RM734 was investigated and is discussed in depth as halogen substitution on the liquid crystal molecule can alter the quantum mechanical properties of any liquid crystal molecule. Density functional theory combined with B3LYP and dispersion correction were used to calculate the properties of RM734. The 6-311G** basis set was used for the estimation of these properties, whereas def2-TZVPD was used to evaluate the nonlinear optical parameters. Due to the halogenation of RM734, its electronic properties vary significantly. By halogenation, a better electron-transport molecule can be converted into a hole-transport molecule. The electro-optical properties were calculated with the application of an external electric field for all molecules. With the help of the order parameter, the nematic phase was observed for all reported molecules. The variation in the birefringence with respect to the external electric field was investigated and discussed in detail. Therefore, the present study reveals the significant impact of halogenation in terms of the nonlinear optical and thermochemical properties of RM734. [ABSTRACT FROM AUTHOR]

Norfloxacin (NOX), a broad spectrum fluoroquinolone (FQ) antibiotic, is commonly detected in environmental residues, potentially contributing to biological drug resistance. In this paper, an aptamer recognition probe has been used to develop a label-free liquid crystal-based biosensor for simple and robust optical detection of NOX in aqueous solutions. Stimuli-receptive liquid crystals (LCs) have been employed to report aptamer–target binding events at the LC–aqueous interface. The homeotropic alignment of LCs at the aqueous–LC interface is due to the self-assembly of the cationic surfactant cetyltrimethylammonium bromide (CTAB). In the presence of the negatively charged NOX aptamer, the ordering changes to planar/tilted. On addition of NOX, the aptamer–NOX binding causes redistribution of CTAB at the LC–aqueous interface and the homeotropic orientation is restored. This results in a bright-to-dark optical transition under a polarized optical microscope (POM). This optical transition serves as a visual indicator to mark the presence of NOX. The devised aptasensor demonstrates high specificity with a minimum detection limit of 5 nM (1.596 ppb). Moreover, the application of the developed aptasensor for the detection of NOX in freshwater and soil samples underscores its practical utility in environmental monitoring. This proposed LC-based method offers several advantages over conventional detection techniques for a rapid, feasible and convenient way to detect norfloxacin. [ABSTRACT FROM AUTHOR]

Delayed luminescence (DF), including phosphorescence and thermally activated delayed fluorescence (TADF), and circularly polarized luminescence (CPL) exhibit common and broad application prospects in optoelectronic displays, biological imaging, and encryption. Thus, the combination of delayed luminescence and circularly polarized luminescence is attracting increasing attention. The encapsulation of guest emitters in various host matrices to form host–guest systems has been demonstrated to be an appealing strategy to further enhance and/or modulate their delayed luminescence and circularly polarized luminescence. Compared with conventional liquid crystals, polymers, and supramolecular matrices, porous crystalline frameworks (PCFs) including metal–organic frameworks (MOFs), covalent-organic frameworks (COFs), zeolites and hydrogen-bonded organic frameworks (HOFs) can not only overcome shortcomings such as flexibility and disorder but also achieve the ordered encapsulation of guests and long-term stability of chiral structures, providing new promising host platforms for the development of DF and CPL. In this review, we provide a comprehensive and critical summary of the recent progress in host–guest photochemistry via the encapsulation engineering of guest emitters in PCFs, particularly focusing on delayed luminescence and circularly polarized luminescence. Initially, the general principle of phosphorescence, TADF and CPL, the combination of DF and CPL, and energy transfer processes between host and guests are introduced. Subsequently, we comprehensively discuss the critical factors affecting the encapsulation engineering of guest emitters in PCFs, such as pore structures, the confinement effect, charge and energy transfer between the host and guest, conformational dynamics, and aggregation model of guest emitters. Thereafter, we summarize the effective methods for the preparation of host–guest systems, especially single-crystal-to-single-crystal (SC–SC) transformation and epitaxial growth, which are distinct from conventional methods based on amorphous materials. Then, the recent advancements in host–guest systems based on PCFs for delayed luminescence and circularly polarized luminescence are highlighted. Finally, we present our personal insights into the challenges and future opportunities in this promising field. [ABSTRACT FROM AUTHOR]

The crystallization behavior of halide perovskites is of great significance. Fractal structures, featured by self-similarity between local morphology and global structures, have consistently captivated scientists' interest across diverse disciplines. In this study, we realized the fractal patterns in lead-free zero-dimensional (0D) Cs2InBr5(H2O) perovskites. By depositing saturated precursor droplets on silicon or glass substrates, we initiated nucleation and crystallization of 0D Cs2InBr5(H2O) crystals on the liquid's upper surface. As the solution evaporated, the remaining high-concentration solution formed self-similar fractal patterns beneath the Cs2InBr5(H2O) crystals. This anisotropic growth mechanism imparted a unique self-assembly behavior to 0D Cs2InBr5(H2O). Additionally, X-ray diffraction results confirmed distinct preferential orientations of the fractal patterns. The findings of this work provide valuable insights into the controlled crystallization behavior of lead-free perovskites and inspire further exploration of novel optoelectronic properties arising from such a unique fractal pattern. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have emerged as a new class of materials, displaying a unique capability to self-assemble into micelles, liposomes, liquid crystals, and microemulsions. Despite evident interest, advancements in the controlled formation of amphiphilic ILs remain in the early stages. Taking inspiration from nature, we introduced the concept of lipid-like (or lipid-inspired) ILs more than a decade ago, aiming to create very low-melting, highly lipophilic ILs that are potentially bio-innocuous – a combination of attributes that is frequently antithetical but highly desirable from several application-specific standpoints. Lipid-like ILs are a subclass of functional organic liquid salts that include a range of lipidic side chains such as saturated, unsaturated, linear, branched, and thioether while retaining melting points below room temperature. It was observed in several homologous series of [Cnmim] ILs that elongation of N-appended alkyl chains to greater than seven carbons leads to a substantial increase in melting point (Tm) – which is the most characteristic feature of ILs. Accordingly, it is challenging to develop ILs with low Tm values while preserving their hydrophobicity and self-organizing properties. We found that two alternative Tm depressive approaches are useful. One of these is the replacement of the double bonds with thioether moieties in the alkyl chains, as detailed in several published papers detailing the chemistry of these ILs. Employing thiol–ene and thiol–yne click reactions is a facile, robust, and orthogonal method to overcome the challenges associated with the synthesis of alkyl thioether-functionalized ILs. The second approach involves replacing the double bonds with the cisoid cyclopropyl motif, mimicking the strategy used by certain organisms to modulate cell membrane fluidity. This discovery has the potential to greatly impact the utilization of lipid-like ILs in various applications, including gene delivery, lubricants, heat transfer fluids, and haloalkane separations, among others. This feature article presents a concise, historical overview, highlighting key findings from our work while offering speculation about the future trajectory of this de novo class of soft organic-ion materials. [ABSTRACT FROM AUTHOR]

Three naphthorosarins, antiaromatic expanded porphyrins bearing different meso substituents (NRos 1–3), designed to self-assemble into columnar liquid crystalline (LC) structures, were synthesized and characterized using polarized optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), as well as supporting computational calculations. The substituents were found to play a crucial role in modulating the LC behaviour. [ABSTRACT FROM AUTHOR]

The potential of azobenzene derivatives that can undergo photoinduced solid-to-liquid transition at room temperature has been demonstrated in many fields such as photo-actuators, energy storage and photo-switchable adhesives. However, both their natural yellowish colour and slow liquid-to-solid phase transition restoration limit their universality in applications. Here, a colourless N-benzylideneaniline derivative molecule with asymmetric side-group substitution (MCN) is synthesized. The small molecular crystal of MCN achieves a reversible photoinduced crystal-to-isotropic liquid transition at room temperature. Due to the short half-life of MCN metastable isomers, the phase transition restoration rate here is significantly faster than that of azobenzene derivatives. As a result, only a single wavelength light source is needed to achieve complete phase change control. The phase transition behaviour of MCN is in situ monitored by using a UV-vis absorption spectrometer in a time-driven mode and a polarizing optical microscope, and its phase transition mechanism is proposed. Furthermore, a smart glass with photo-switchable transmittance is developed by mixing an MCN crystal with a commercial liquid crystal (5CB). [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystal polymer network (CLCN) films have attracted much attention for their applications as optical filters and in displays, decoration, and anti-counterfeiting. Herein, two pairs of chiral bola-type epoxy liquid crystals with a cholesteric mesophase were synthesized. Their mixtures exhibit thermochromic behaviour. CLCN films with structural colours were prepared using their mixtures through photopolymerization. The Bragg reflection band and the handedness of the CLCN film can be controlled by changing the weight ratio of the chiral liquid crystals. Patterned CLCN films were prepared based on their thermochromic behaviour, the addition of a luminescent compound, or the handedness of the liquid crystal mixture, and they were potentially applied in decoration and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Chiral liquid-crystalline emitters based on 9,9-dimethyl-10-(4-(phenylsulfonyl)phenyl)-9,10-dihydroacridine and a functionalised binaphthol show smectic liquid crystal phases and circularly polarised blue fluorescence with a high luminescence dissymmetry factor ‖glum‖ of 0.13. Solution-processable organic light-emitting diodes (OLEDs) based on the enantiomers were explored. [ABSTRACT FROM AUTHOR]

Rod-like bolapolyphiles with highly branched carbosilane-based side-chains self-assemble into several honeycomb structures if the oligo(p-phenylene ethynylene) core is polyfluorinated, whereas for the non-fluorinated series an A15 type cubic network of rod-bundles was observed instead, suggesting a brand new pathway for the transition between triangular and square honeycomb phases. [ABSTRACT FROM AUTHOR]

A series of new gold nanocomposite materials, GNC_LCx (x = 6–11), was obtained from a series of non-linear liquid crystal oligomers, LCx (x = 6–11), with a gold nanocluster (GNC) possessing a formulation of [Au25(SC12H25)18]TOA, which is represented as Au25. The oligomers consist of a central disulphide (S–S) linkage wherein the length of the inner alkyl spacer n1 varied from 6 to 11, whilst the outer alkyl length n2 was fixed at 6. The synthesis of Au25 was verified using UV-vis and TEM, whereas the properties of Au25, LCx, and GNC_LCx were validated using UV-vis, PL, DLS, and TEM. However, the fundamental results of GNC_LCX suggest the possibility of core alteration, indicating that the GNC in GNC_LCx may no longer be the same Au25. The occurrence of some kind of complexation or more than one intermolecular interaction (other than hydrophobic interaction) is proposed that might contribute to the exisiting outcome. The primary findings implied that the synthesis of the nanocomposites was successful and the enhancement of the thermal stability of the transition temperatures of crystal–isotropic (TCr–I) and isotropic–nematic (TI–N) transitions along with the photoluminescence property were observed. [ABSTRACT FROM AUTHOR]

Blue phase (BP) liquid crystals represent a fascinating state of soft matter that showcases unique optical and electro-optical properties. Existing between chiral nematic and isotropic phases, BPs are characterized by a three-dimensional cubic lattice structure resulting in selective Bragg reflections of light and consequent vivid structural colors. However, the practical realization of these material systems is hampered by their narrow thermal stability and multi-domain crystalline nature. This feature article provides an overview of the efforts devoted to stabilizing these phases and creating monodomain structures. In particular, it delves into the complex relationship between geometrical confinement, induced curvature, and the structural stability and photonic features of BPs. Understanding the interaction of curved confinement and structural stability of BPs proves crucially important for the integration of these materials into flexible and miniaturized devices. By shedding light on these critical aspects, this feature review aims to highlight the significance of understanding the coupling effects of physical and mechanical forces on the structural stability of these systems, which can pave the way for the development of efficient and practical devices based on BP liquid crystals. [ABSTRACT FROM AUTHOR]

Hetero-bimetallic liquid crystalline materials, exhibiting a single Colhex mesophase, were obtained by simple chemical blending between two structurally-related Cu(II) and Zn(II) metallomesogens based on 1,10-phenanthroline and two chelating gallate ligands. Mesomorphous and optical properties were modified upon their relative respective proportions. This study highlights the numerous possibilities for the fabrication of new multifunctional polymetallic materials, with the possibility of tuning the properties and controlling supramolecular interactions between metal centres and corresponding synergistic effects. [ABSTRACT FROM AUTHOR]

"Chemical Communications" is a journal dedicated to sustainable chemistry and new solutions for an open, green, and inclusive future. The featured research from Professor Ichikawa's laboratory at Tokyo University of Agriculture and Technology focuses on the design of V-shaped ionic liquid crystals with atropisomerisation ability and the formation of double-gyroid molecular assemblies. The article also discusses organoboron catalysis for direct amide/peptide bond formation. [Extracted from the article]

We report columnar liquid-crystalline thiophene-oxadiazole molecules, which can be oriented by electric field and exhibit photodiode properties with an open-circuit voltage of 1 V. Their yellow luminescence can be excited by UV-visible or infrared light. Their room-temperature phosphorescence turns brighter upon heating. [ABSTRACT FROM AUTHOR]

Oil-in-water (O/W) emulsions with lamellar liquid crystal interfaces are promising drug-delivery systems for topical formulations. In this study, a novel delivery system—an O/W liquid crystal emulsion system containing an oil crystal network—was constructed by introducing a fully hydrogenated soybean oil (HSO) to a liquid crystal emulsion, and then the properties of the system were studied in detail. The results showed that with the introduction of the HSO, the Maltese cross patterns of the liquid crystal interface became brighter and subtle crystals of HSO gradually appeared in the inner of the liquid crystal texture. The aliphatic acid and triacylglycerols (TAGs) in HSO participated in the orderly arrangement of the lamellar interfacial phase, which not only benefited the formation of liquid crystals and recovery of the interfacial dynamic equilibrium at higher temperature but also endowed the system with a stronger interfacial film and better thermal stability. The aliphatic acid and TAGs recrystallized inside the emulsion droplets, forming a crystal network inside the droplets. The combination of HSO crystals and liquid crystals increased the characteristic temperature (Tc) of the liquid crystals and decreased the HSO melting point, which benefited the display performance of the liquid crystal emulsion and the effective application of the HSO. At the same time, the formation of both a strengthened interfacial film of liquid crystal and three-dimensional HSO crystal network inside the droplets made the emulsion system show better storage stability, mechanical strength, and deformation resistance. Furthermore, the unique structure of the liquid crystal emulsion containing HSO crystals endowed the system with an excellent sustainable release property and potential application prospects in medicine, personal care, and other fields. The present study not only provides an effective delivery system but also expands the application potential of HSO and liquid crystal emulsion systems in practice. [ABSTRACT FROM AUTHOR]

The research on superhalogens has successfully completed four decades. After their prediction in 1981 and experimental verification in 1999, such species have attracted attention due to their unusual structures and intriguing applications. Superhalogens are species whose electron affinity exceeds that of halogen or whose anions possess a larger vertical detachment energy than that of halides. Initially, these species were designed using s and p block atoms having a central electropositive atom as the core with excess electronegative atoms as ligands such as F, Cl, O etc. The last decade has witnessed enormous progress in the field of superhalogens. The transition metal atoms have played the role of the central core and a variety of new ligands have been explored. Further, new classes of superhalogens such as polynuclear superhalogens, magnetic superhalogens, aromatic superhalogens, etc. have been reported. The first application of superhalogens as strong oxidizers appeared much before their conceptualization. In the last decade, however, their applications have spanned a variety of fields such as energy storage, superacids, organic superconductors, ionic liquids, liquid crystals, etc. This makes research in the field of superhalogens truly interdisciplinary. This article is intended to highlight the progress on the design and applications of superhalogens in the last decade. [ABSTRACT FROM AUTHOR]

Hydrogen-bonded complexes are formed between two chain lengths of 4-alkoxystilbazoles and six different chlorophenols. Single crystal structure determinations were possible for four of the complexes, all of which showed a similar dimeric motif in which two chlorophenols formed a loose back-to-back dimer with a stilbazole hydrogen-bonded at either side. Two of the complexes showed similarities in their three-dimensional packing. Liquid crystal properties were found for all complexes except those containing pentachlorophenol. The phase behaviour of the longer-chain dodecyloxystilbazole complexes was dominated by the observation of the smectic A phase, while both nematic and smectic A phases were found for the octyloxy homologues. The mesophase stability was appreciably lower in these new complexes when compared with fluorophenol analogues reported previously, attributed to a reduction in anisotropy on account of the effects of the greater size of chlorine compared with fluorine. [ABSTRACT FROM AUTHOR]

The synthesis and characterisation of four series of symmetric liquid crystal dimers containing either alkylthio or alkyloxy terminal chains are reported. The (E,E)-[pentane-1,5-diylbis(oxy-4,1-phenylene)]bis{N-[4-(alkyloxy)phenyl]methanimine}s, mO.O5O.Om and (E,E)-[hexane-1,6-diylbis(oxy-4,1-phenylene)]bis{N-[4-(alkyloxy)phenyl]methanimine}s, mO.O6O.Om series are nematogenic when the terminal chains are short whereas the higher homologues show the smectic A phase. The mO.O6O.Om series shows higher clearing temperatures regardless of the terminal chain length. The (E,E)-[pentane-1,5-diylbis(oxy-4,1-phenylene)]bis{N-[(alkylthio)phenyl]methanimine}s, mS.O5O.Sm series is solely nematogenic, and does not show liquid crystallinity when m ≥ 5. The (E,E)-[hexane-1,6-diylbis(oxy-4,1-phenylene)]bis{N-[(alkylthio)phenyl]methanimine}s, mS.O6O.Sm series, however, shows mesogenic behavior over the entire series, with the smectic C phase only emerging when the terminal chain is long, m ≥ 8. In general, for a given spacer length, the dimers containing alkyloxy chains show the highest clearing temperatures and the alkylthio chains the lowest. For the shortest terminal chains, however, the nematic–isotropic transition temperatures of the alkylthio materials are higher than those containing the alkyl chain. This behaviour is rather general and discussed in terms of steric and electronic interactions. [ABSTRACT FROM AUTHOR]

In this communication, we report a new class of oscillation mode, dome-shaped mode (DSM), in liquid crystal (LC) microlasers. A record high Q-factor over 24 000 is achieved in LC soft-matter microlasers. We successfully presented a proof-of-concept demonstration of red, green, blue (RGB) LC-DSM microlaser pixels with a 74% broader achievable color gamut than the standard RGB color space. Besides, the detection limit for acetone vapor molecules is as low as 0.5 ppm, confirming the excellent potential of the proposed LC-DSM microlaser in ultra-high sensitivity detection. [ABSTRACT FROM AUTHOR]

This paper reports fluorescein-linked calixarene-based columnar liquid crystals with a broad temperature range of mesophases. The photophysical and density functional theory (DFT) study suggested good electronic behaviour and reactivity of supramesogens. All the synthesized materials (4a–4d) were characterized by FT-IR, 1HNMR, 13C NMR, MALDI-TOF, and elemental analysis and displayed yellow to orange light emission in the solution, thin films, and solid state. Further, all materials showed aggregation-induced emission (AIE) effect with higher quantum yields. The fluorescein-linked supramolecules broadly stabilized the columnar hexagonal phase and formed self-assembly with higher thermal stability. The substituted alkoxy side chains on the terminal position influenced the mesophase temperature range and thermal stability. All the compounds adopted cone conformation, which was confirmed by experimental and computational studies. Further, these fluorescent materials were used to stain model organism nematodes in solution-state aggregation. [ABSTRACT FROM AUTHOR]

A new series of lower-rim-functionalized octa-substituted resorcin[4]arene-based supramolecular compounds with variable alkoxy side chains (–OC4H9, –OC6H13, –OC8H17, –OC10H21) has been synthesized by a simple two-step procedure. The proposed method is suitable for preparing lower-rim-functionalized resorcinarene-based compounds on a large scale and it is cost-effective as compared to other reported supramesogens. All four functionalized compounds displayed a columnar hexagonal phase (Colh) over a high mesophase temperature range. The optical texture and thermal behaviour of the target compounds were identified by POM and DSC studies and the molecular organization in the mesogenic state was further confirmed by PXRD. The molecular system based on a resorcinarene core with symmetrical substitution of alkyl arms exhibited columnar type self-assembly organization. All four supramolecules with different side alkyl spacers showed high thermal stability. Compound D4 with a decyloxy side chain was further optimized to implicate as optical window and transport layer in solar cells to replace the commercially available toxic Cd-based compound. Herein, we developed thin films of compound D4 on glass and Indium doped Tin oxide glass substartes followed by subjecting the prepared thin films to the characterization tools to explore optical and electical properties. The current–voltage relation shows ohmic-type behaviour. The optical properties display high transmittance in the far visible and NIR regions for all the developed thin films. The derivative showed optical energy band gaps of 1.61 eV, 4.01 eV and 2.27 eV for as deposited and film anneaeld at 100 °C and 200 °C, respectively and findings warrants its suitability for use as an ecofriendly optical window and transport layer in second and third generation solar cells. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystals (ChLC) with helical molecular structures are known for their ability to selectively reflect light at specific wavelengths. In this study, broadband reflective polymer-stabilized cholesteric liquid crystal (PSCLC) films in the near-infrared region were prepared by spin-coating MoO2 nanoparticle (NP) dispersions. The effects of the dispersion concentration, the concentration of the polymerizable monomer, the light intensity and the polymerization time on the reflection wavelength were studied. The reflection bandwidth of the PSCLC film was broadened from 261 nm to 401 nm. It is confirmed that NPs have photothermal conversion ability, and their diffusion in the liquid crystal composite system is beneficial to the formation of non-uniform pitch distribution. Therefore, the PSCLC film prepared by the NP diffusion method is expected to be used for dynamic control of the sunlight transmission of energy-saving glass in buildings. [ABSTRACT FROM AUTHOR]

Supramolecular gels and liquid crystals are two important organic soft materials in self-assembly systems. A series of new low-molecular-weight organic gels was synthesized by connecting two cholesterol molecules and two hydrophobic chains incorporating amide groups to a central tetrathiafulvalene (TTF) moiety (1a–l). Compounds 1a–l and their corresponding charge transfer complexes easily formed a stable supramolecular gel in various organic solvents and their self-assembly morphologies and structures were investigated. It was revealed that hydrogen bonding and van der Waals interaction played important roles in the gelation process. More importantly, nearly half of the gelators exhibited liquid crystalline phases of type smectic A in a particular temperature region; there was no crystallization but there was vitrifying to form glassy mesogens during cooling from the isotropic melt. The effects of the linker chain length and terminal alkoxy chain on liquid crystals were studied. The liquid crystalline organogelator with TTF unit was first designed and synthesized. It was demonstrated that the gelators obtained from cyclohexane had a strong ability to adsorb the toxic dye Rhodamine B from water. This property of this series of compounds is considered to have potential utilization for the removal of toxic dye molecules from wastewater. [ABSTRACT FROM AUTHOR]

In their thermotropic liquid-crystalline state, molecular semiconductors can show charge transport with high carrier mobility. Polymerization of the corresponding mesogens into a cross-linked network often deteriorates the charge transport. Here, we report that mesogens consisting of a terthiophene core and discrete oligodimethylsiloxane side-chains terminated by acrylate units can be photopolymerized in the columnar phase with retention of nanoscale order and charge transport capabilities. We argue that the strong tendency for microphase segregation protects the semiconducting block from reacting with free radicals during polymerization. This work provides new insights into the design of electroactive materials with charge transport properties. [ABSTRACT FROM AUTHOR]

The synthesis and phase-transition behavior of a novel homologous series of 4′-alkylseleno-4-cyanobiphenyls [nSeCB, where n represents the number of carbon atoms in the alkyl chains (n = 1–8)] is reported. Polarized optical microscopy and differential scanning calorimetry revealed that the nSeCB homologs with n = 1–6 exhibited monotropic nematic (N) phases at low temperatures, which appeared below 10 °C for nSeCB with n = 3–6. However, no liquid crystal (LC) phase was observed in the nSeCB with n = 7 and 8. In addition, we compared the phase-transition behaviors of the nSeCB homologs with those of the alkyl-, alkoxy-, and alkylthio-based homologous series (nCB, nOCB, and nSCB, respectively). The LC phases of certain nCB and nOCB were enantiotropic, whereas those of all nSCB and nSeCB were monotropic. The longer-chain nCB, nOCB, and nSCB homologs formed layered smectic A (SmA) phases, whereas only N phases were observed for the nSeCB homologs within the tested range of the chain lengths. The nSeCB series showed the lowest isotropic-to-N phase-transition (TIN) temperatures for all chain lengths except 1SeCB. The low mesogenic ability and LC phase-transition temperatures of nSeCB were attributed to the higher flexibility, steric bulk, and lower molecular anisotropy due to the C–Se–C bond, which has lower rotational barriers, longer bond lengths, and smaller bond angles than the other bonds compared herein. The varying alkyl-chain lengths had a greater influence on the phase-transition temperatures of the nSeCB homologs than those of the other homologs. Furthermore, the single-crystal structural analysis of 1SeCB was conducted to obtain insights into the phase-transition behaviors. [ABSTRACT FROM AUTHOR]

The polypeptide chain is an important structural unit that forms the secondary structure of proteins via intermolecular amide-type N–H⋯O＝ hydrogen bonds. In contrast, alkylamide chains (–CONHCnH2n+1) are interesting structural units in which an amide group with a dipole moment and an alkyl chain with high conformational freedom coexist, which have been used to form characteristic molecular assembly structures such as liquid crystals, gels, and supramolecular polymers. One-dimensional chains based on intermolecular N–H⋯O＝ hydrogen-bonding interaction form these molecular assemblies. In the liquid crystal, an electric field – polarization hysteresis curve was observed for alkylamide-substituted benzene derivatives. A molecular design based on the combination of the alkylamide chain, which is the origin of ferroelectricity, and the functional π-electron framework enables the coexistence of ferroelectricity with luminescence, high thermal stability, photoresponse, and current switching properties, and the fabrication of multifunctional molecular materials. The introduction of chiral alkylamide chains is also effective in controlling unidirectional dipole inversion and low coercive electric fields for low-energy-consumption memory devices. Alkylamide chains in molecular assemblies are useful for the development and control of the physical properties of organic ferroelectrics that realize the rotational dynamics of polar amide groups coupled with the melting of alkyl chains in the liquid crystal and solid states. [ABSTRACT FROM AUTHOR]

Microlasers integrated with biological systems have received tremendous attention for their intense light intensity and narrow linewidth recently, serving as a powerful tool for studying complex dynamics and interactions in scattered biological micro-environments. However, manipulation of microlasers with controllable motions and versatile functions remains elusive. Herein, we introduce the concept of motor-like microlasers formed by magnetic-doped liquid crystal droplets, in which the direction and velocity could be controlled by altering internal magnetic nanoparticles or external magnetic fields. Both translational and rotatory motions of the lasing resonator could be continually changed in real-time. Lasing-encoded motors carrying different functions and lasing wavelengths were also achieved. Finally, we demonstrate the potential of motor-like microlasers by functioning as a localized stimulation emission light source to stimulate or illuminate living cells, providing a novel approach for switching on/off light emissions and subcellular imaging. Laser emitting micromotors offer a facile system for precise manipulation of microlasers in biological fluids, providing new insight into the development of programmable on-chip laser devices and laser-emitting intelligent systems. [ABSTRACT FROM AUTHOR]

Photonic materials with a periodic change of refractive index show unique optical properties through wavelength-selective diffraction and modulation of the optical density of state, which is promising for various optical applications. In particular, photonic structures have been produced in the format of microparticles using emulsion templates to achieve advanced properties and applications beyond those of a conventional film format. Photonic microparticles can be used as a building block to construct macroscopic photonic materials, and the individual microparticles can serve as miniaturized photonic devices. Droplet microfluidics enables the production of emulsion drops with a controlled size, composition, and configuration that serve as the optimal confining geometry for designing photonic microparticles. This feature article reviews the recent progress and current state of the art in the field of photonic microparticles, covering all aspects of microfluidic production methods, microparticle geometries, optical properties, and applications. Two distinct bottom-up approaches based on colloidal assembly and liquid crystals are, respectively, discussed and compared. [ABSTRACT FROM AUTHOR]

Photoresponsive nanostructured materials are of great importance for photonic applications. Herein we report the design, synthesis, and liquid crystal (LC) self-assembly of two new series of photoresponsive hockey-stick LCs (HSLCs). The new HSLCs are azobenzene-based polycatenars derived from the 4-cyanoresorcinol bent-core unit. The long arm is a fork-like triple alkoxylated wing, while the short arm is terminated with a single variable alkoxy chain. The molecular self-assembly of these HSLCs is characterized using polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and electro optical measurements. In both series of LC materials differing in the chain volume at the crowded end, wide temperature ranges of lamellar Smectic A phases (up to 170 K) are observed beside achiral isotropic liquid phases (Iso1) for the shorter derivatives. On chain elongation helical self-assembly of the π-conjugated rods in networks occurs resulting in the formation of nanostructured bicontinuous cubic network phases with Ia3¯d space group (Cubbi/Ia3¯d), in most cases stable even around room temperatures on cooling. At the transition from SmA to Cubbi phases, an additional unknown three-dimensional (3D) phase is formed. A possible explanation for the disappearance of the triple network Cubbi phases with I23 symmetry (Cubbi[*]/I23) in these HSLCs is represented based on the phase behaviour of a new material having the central 4-cyanoresorcinol unit shifted to a terminal position of the rod-like core. Finally, the reversible trans–cis photoisomerization for some selected examples was investigated in chloroform solution. [ABSTRACT FROM AUTHOR]

Liquid crystalline (LC) dimers formed helical nanofilaments depending on the parity of the alkyl linker, revealing an unusual odd–even effect. Molecular dynamics simulations were used to investigate the observed tendency. Elongation of the linker translates to an increase of the pitch of the helices, which allows achieving tuneable helical assemblies of Au nanoparticles doped to the LC matrix. The impact of the tuneable pitch of helices on the chiral optical properties of composites was investigated with full-wave simulations based on the T-matrix method. [ABSTRACT FROM AUTHOR]

Multiple-emulsion drops serve as versatile templates to design functional microcapsules due to their core–shell geometry and multiple compartments. Microfluidics has been used for the elaborate production of multiple-emulsion drops with a controlled composition, order, and dimensions, elevating the value of multiple-emulsion templates. Moreover, recent advances in the microfluidic control of the emulsification and parallelization of drop-making junctions significantly enhance the production throughput for practical use. Metastable multiple-emulsion drops are converted into stable microcapsules through the solidification of selected phases, among which solid shells are designed to function in a programmed manner. Functional microcapsules are used for the storage and release of active materials as drug carriers. Beyond their conventional uses, microcapsules can serve as microcompartments responsible for transmembrane communication, which is promising for their application in advanced microreactors, artificial cells, and microsensors. Given that post-processing provides additional control over the composition and construction of multiple-emulsion drops, they are excellent confining geometries to study the self-assembly of colloids and liquid crystals and produce miniaturized photonic devices. This review article presents the recent progress and current state of the art in the microfluidic production of multiple-emulsion drops, functionalization of solid shells, and applications of microcapsules. [ABSTRACT FROM AUTHOR]

Selective 2-dimensional (2D) nanoporous polymer films have been developed using a templating method based on hydrogen-bonding supramolecular liquid crystals (LCs) containing benzoic acid and pyridine groups (6OBA·NC6·C6H). The smectic lamellar structures are maintained and anionic nanopores are obtained after template (NC6) removal. The NC6-removed polymer films demonstrate anisotropic adsorption toward cationic dye methylene blue (MB) with a high adsorption capacity of 688 mg g−1 under planar alignment. The specific pore dimension with anionic interior shows size- and charge-selectivity. The effects of pore size and pore charges on MB adsorption are investigated using the NC6-removed films with extra pores or non-charged pores, respectively. 5CB is used as the intermolecular template to produce extra nanopores. The obtained results show that the equilibrium adsorption capacity (qe) of MB onto the NC6/5CB template-removed film (T-removed film) does not increase evidently. Non-charged pores generated from the hydrochloric acid (HCl) treatment of the NC6-removed film show poor dye adsorption, indicating that pore charges strongly affect MB adsorption because carboxylate groups act as the active adsorption sites and electrostatic interactions contribute to MB adsorption. Adsorption kinetics can be well described using the pseudo-second-order kinetic model. Also, satisfactory regenerability of the functional polymer films can be achieved by simple HCl treatment and ethanol washing. Such functional polymer films with desired pore dimensions and pore charges can serve as excellent adsorbents to effectively remove cationic contaminants from polluted water. [ABSTRACT FROM AUTHOR]

Multiple mesophases, including the smectic A phase (Sm A), chiral nematic phase (N*), and blue phase (BP I), were seen in a series of non-symmetric bent mesogenic dimers containing a cholesteryl benzoate group. FTIR, 1H-NMR, DSC, POM, UV, and XRD were used to analyze the chemical structure and liquid crystal characteristics of the dimers. The phase transition occurred when the azobenzene structure was treated with UV light, changing the structure of the molecules. There is evidence that when the length of the terminal alkoxy chain is longer than the flexible spacer, it exhibits a smectic A phase as well as a chiral nematic phase; however, when the length of the flexible spacer is shorter than the length of the terminal alkoxy chain, it only exhibits a chiral nematic phase. [ABSTRACT FROM AUTHOR]

The truxene molecule is more versatile and widespread than ever imagined. At the end of the last century, this star-shaped structure was recognized mostly in liquid crystals. However, the development of optoelectronics resulted in a revolution in truxenes. Stable, fast, easily processed and cheap optoelectronic devices are desirable in many areas of industry and science. Consequently, the contribution of truxenes to these fields is manifold, ranging from D-A emitters, semiconductors, and complexes to sensors. They attract attention because of their relatively low mass and expanded p-electron system. Symmetric molecules give rise to dendrimers, bowl-shape molecules and fullerenes. Further advantages are shown by the recently discovered non-symmetric truxenes obtained via one-or twoheteroatom displacement. Thus, the chemistry of new heteroaromatic compounds has been expanded. [ABSTRACT FROM AUTHOR]

Two series of regio-isomeric butterfly-shaped liquid crystalline systems, based on a ditriphenylenothiophene core (α/β-DTPT) equipped with eight peripheral long alkoxy chains, were synthesized in two steps by the Suzuki-Miyaura cross-coupling/Scholl cyclo-dehydrogenation reactions tandem from appropriate precursors. The influence of the core topology (i.e. positional isomerism) on the mesomorphism, gelling self-assembly, absorption and luminescence, and charge-transport properties of both sets of isomers was investigated and compared. The six fused π-conjugated molecules systematically display columnar hexagonal (Colhex) mesophases with β-fused ditriphenylenothiophene compounds (DTPTBn) showing more extended mesophase ranges and higher phase transition temperatures than their isomeric α-counterparts (DTPTAn). All ditriphenylenothiophenes also show strong aggregation behavior in organic solvents, and, in addition, good organic gelling abilities were found for the β-isomers. Interestingly too, high hole mobility rates greater than 10-3 cm2 V-1 s-1 were measured for the β-isomers, which were about 10 times higher than those of the α-counterparts. Modeling of the molecular structures combined with DFT calculations showed that the β-isomers possess flatter and more extended π-conjugated cores than the slightly distorted α-isomers, and consequently were more prone to optimize π-π intermolecular interactions, in agreement with the high-temperature mesophases and high charge carrier mobilities observed for these isomers. Finally, both sets of compounds emit blue-purple light in solution and the emission is substantially redshifted when organized in films. DFT calculations of the HOMO-LUMO energy levels were also consistent with the optical measurements. This original molecular design and straightforward synthesis combination provides an efficient way to obtain novel π-extended organic, potentially semiconductor materials for further electronic device investigations. [ABSTRACT FROM AUTHOR]

Liquid crystals (LCs) containing an azo group are often used in the construction of molecular systems that present both mesomorphic features and reversible photoisomerization. The interest in the search for new materials of this type is related to a better understanding and improvement of their performance. Therefore, this work presents the synthesis and characterization of seven new organic azo compounds with a star-shaped disk-like molecular structure, of which three exhibited the properties of columnar LCs. The molecular structures vary in the rigid core size, the functional linker group (ester, amide or 1,3,4-oxadiazole heterocycle), and the number and type of peripheral alkoxy chains. Our model structure shows high range Colh mesomorphism especially due to the possibility of intermolecular hydrogen bonding, which was extinguished when the amide group was changed to an azo group, so that no LC phases were observed for smaller molecules, even when branched chains were employed. However, we demonstrate how to surpass the absence of hydrogen bonding through tailoring cohesive forces and space filling by the increment of the rigid core and number of alkoxy chains, stabilizing Colh mesophases with a good range, as confirmed by POM, DSC and XRD analysis. Furthermore, due to the presence of the azo group, UV-vis, ¹H NMR and POM analysis confirmed the reversible photoisomerization for the products in solution and in the Colh mesophase, with significant stability against thermal relaxation of the Z isomer. This demonstrates that, for these materials, the mesomorphism can be reversibly extinguished and regenerated through external factors such as light and temperature. [ABSTRACT FROM AUTHOR]

Liquid crystal oligomers, namely dimers, trimers and tetramers, consisting of cyanobiphenyl and benzylideneaniline-based mesogenic units connected by either linear or bent alkoxy or alkyl spacers are reported. These materials, although built from achiral molecules, show the spontaneously chiral heliconical twist-bend nematic (NTB) phase. We report the relationships between the shape of the oligomer, and the NTB phase stability, the temperature dependence of the helical pitch length and tilt angle, birefringence, and elastic constants. [ABSTRACT FROM AUTHOR]

Herein, a signal-on liquid crystal microarray (LCM) sensor is designed for the first time with a micro-spectral optical sensing signal. Depending on the change of the orientation of the LC molecules in the LCM films and the intensity of the spectral peaks of the PhCs, the signal-on LCM biosensor achieves the detection of AFB1 and the Partial Response Mechanism (PSM) of the LCM films is discovered. [ABSTRACT FROM AUTHOR]

To describe the effects of the alkylthio groups on the phase transition behavior of organic liquid crystal (LC) molecules and their causes, we herein scrutinize the melting points (Tm) and nematic (N)–isotropic phase transition temperatures (TNI or TIN) of alkylthio-, alkoxy-, and alkyl-based LC homologues. To begin with, phase transitions are compared for three homologous series of 4-cyanophenyl benzoates bearing 4-alkyl-, 4-alkoxy-, and 4-alkylthio groups (denoted by nCPB, nOCPB, and nSCPB, respectively) with different alkyl chains (CnH2n+1; n = 1–8). In contrast to nCPB and nOCPB, some of which exhibit enantiotropic N phases, all alkylthio-based nSCPB are found to display monotropic N phases. The nSCPB homologues exhibit higher Tm than not only their corresponding nCPB for all n but also nOCPB counterparts in the case of long chains (n ≥ 6); a similar trend is confirmed also for the Tm values of the structurally similar biphenyl- and cyanobiphenyl-based homologues. Meanwhile, the TNI or TIN values of nSCPB and nCPB are lower than those of nOCPB for all n, and higher for nSCPB than for nCPB with the short chains (n = 1 and 2) but comparable with one another for the longer chains (n ≥ 3). In addition, our discussion addresses more anisotropic 1,4-phenylene bis(benzoate) LCs with alkylthio and alkoxy groups. Furthermore, single-crystal structures of three LC molecules with methylthio groups are examined. Several interatomic contacts around the sulfur atoms such as S⋯HC contacts are indicated, which differ for respective molecules. The present study draws the following conclusions. The alkylthio groups mostly play the role of decreasing the phase transition temperatures (especially TNI or TIN) and hindering LC formation for organic rod-like molecules, primarily due to conformational flexibility, steric bulkiness, and lower molecular anisotropy imposed by C–S–C. The sulfur atom contributes to intermolecular attractive interactions, which are reflected in phase transitions as spatially averaged phenomena (i.e., dispersion force and more polarizable π-systems). The influence of those interactions become more pronounced with lengthening alkyl chains. [ABSTRACT FROM AUTHOR]

A mesogenic metallofoldamer [(1R,R-Ni)2Pd] exhibits thermotropic columnar liquid crystalline properties. The metallofoldamer was prepared from two homochiral crescent-shaped precursors having β-diketonate ligands (1R,R-Ni) through bridging by metal complexation; it exhibited a single helicity owing to the overlapping of both ends. The precursor and metallofoldamer formed similar hexagonal columnar phases. The helical metallofoldamer exhibited the hexagonal columnar phase at the higher temperature range owing to its rigid helical mesogenic structure. [ABSTRACT FROM AUTHOR]

Understanding the microviscosity of soft condensed matter is important to clarify the mechanisms of chemical, physical or biological events occurring at the nanoscale. Here, we report that flapping fluorophores (FLAP) can serve as microviscosity probes capable of detecting small changes. By the ratiometric fluorescence analysis, one of the FLAP probes detects a macroscopic viscosity change of a few cP, occurring at the thermal phase transition of a nematic liquid crystal. We discuss the impact of the chemical structure on the detection capability, and the orientation of the FLAP molecules in the ground and excited states. This work contributes to experimentally providing a molecular picture of liquid crystals, which are often viewed as a continuum. [ABSTRACT FROM AUTHOR]

Planar multiaromatic molecules hierarchically and selectively arrange into nematic chromonic liquid crystals in the room temperature ionic liquid 2-hydroxyethylammonium formate. In a proof of concept, these liquid crystals were used as reaction media to produce mesostructured silica materials under mild biomimetic conditions. Several other applications are envisaged. [ABSTRACT FROM AUTHOR]

Although various perylene derivatives have been studied widely, circularly polarized luminescence (CPL) perylenes in the aggregated state are seldom presented due to the ACQ effect. In this study, a novel diphenylacrylonitrile–perylene derivative with peripheral chiral alkyl chains (CPL-P) was designed and prepared in 81% yield. CPL-P showed Colh mesophase with a wide mesomorphic temperature ranging from 42.8 °C to 155.6 °C. Its photophysical studies suggested good fluorescence emission (550–700 nm) in the aggregated state due to the AIE-FRET effect between the diphenylacrylonitrile unit and perylene skeleton. The chiral optical investigation implied that CPL-P exhibited excellent CPL emission in the aggregated state, which could be attributed to the favourable influence of the AIE-FRET effect and the effective chiral transfer from chiral alkyl chains to the perylene skeleton based on the spiral columnar mesophase. This work not only presents a novel perylene derivative with a good CPL property in the aggregated state, but also opens a new strategy of combining the AIE-FRET effect and chiral transfer based on mesomorphic self-assembly to construct normal dye derivatives with excellent CPL property in the aggregated state. [ABSTRACT FROM AUTHOR]

A series of tetraphenylporphyrin-based thermotropic liquid crystals containing oligo(dimethylsiloxane) were synthesized. These disc–coil hybrids form ordered nanostructures with periodic sizes on the sub-5 nm scale, including oblique columnar, lamellar, and hexagonal columnar phases. Films with sub-5 nm line patterns and homeotropically aligned columnar structures can be obtained by substrate-induced self-assembly. [ABSTRACT FROM AUTHOR]