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Liquid-crystalline dendrimers with donor triphenylene as the peripheral discotic mesogen and acceptor fullerene as the dendrimer core have been designed and synthesized with the aim of achieving heterojunction ambipolar charge-transport columnar materials. While the low-generation fullerene-core discotic liquid-crystalline dendrimers self-organize into a lamellar structure, the co-assembled mixtures through blending with a low-molar-mass triphenylene derivative successfully form hierarchical columnar superstructures with segregated stacking of the triphenylene discs and fullerene moieties in discrete columns. Such donor–acceptor segregated columnar materials exhibit ambipolar charge-transport behavior, with rather high mobilities reaching 0.012 cm2 V−1 s−1 for holes and 0.005 cm2 V−1 s−1 for electrons, as measured by the time-of-flight (TOF) technique. The present work provides a simple and versatile approach for the design of ambipolar conductive columnar liquid-crystalline hybrid dendrimer materials that are promising for organic electronic applications. [ABSTRACT FROM AUTHOR]

Thermotropic ionic liquid crystals (ILCs) are a kind of fascinating functional organic material combining the characteristics and advantages of both liquid crystals (LC) and ionic liquids. Here in this work, a series of supramolecular discotic ILCs of Cn-tri-CTP have been produced through host–guest complexation together with π–π stacking and electrostatic interactions between the readily prepared electrically neutral tris(18-crown-6)triphenylene (tri-CTP) and the facilely available potassium trialkoxybenzenesulfonates with different length alkyl tails of carbon number n = 8, 10, 12, 14, 16. The thus obtained ILC complexes show enantiotropic ordered columnar mesophases, such as center-faced rectangular columnar (Colr) and oblique columnar (Colob) mesophases with broad LC temperature ranges and excellent thermal stability. It is very interesting and fascinating to find that after a simple alignment, such supramolecular discotic ILC complexes in their ordered columnar structures achieve simultaneously anisotropic ionic conductivities as high as 1.99 × 10−2 S cm−1 and hole mobility reaching 4.6 × 10−2 cm2 V−1 s−1, thus exhibiting fantastic dual-channel transport properties both for ions and holes, which may develop into a kind of versatile organic electronic material for various promising unique applications. [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomers (LCEs) combine the ordering character of a liquid crystal and the elasticity of a polymer network. The development of fully light-driven LCE-based soft actuators with good reshapeability and recyclability is in high demand. In this work, we prepared SWCNT/LCE composite films through the introduction of allyl sulfide-based dynamic covalent crosslinks in the LCE matrix and the well-dispersed filler single-walled carbon nanotubes (SWCNTs) with a strong photothermal effect. The SWCNT/LCE composite films were facilely fabricated with reorientation and remouldable capabilities regulated by 405 nm visible light. The monodomain composite films demonstrated multimode actuations of contraction, bending, curling, stretching recovery, and even shape memory driven by 808 nm near-infrared (NIR) light. Moreover, the monodomain spiral ribbon or stretching flat strip and the original polydomain composite film can be readily transformed into each other, and reshaped through easily achievable fabrication conditions. Therefore, the well-prepared SWCNT/LCE composite films with exchangeable covalent crosslinks showed promise as candidates for the development of multimode NIR photomechanical soft actuators with fully light-driven controllability and good remouldability. [ABSTRACT FROM AUTHOR]

The design and preparation of novel liquid crystalline elastomers (LCEs) are highly desirable for the development of smart soft materials with quick stimuli-responsive characteristics. In this work, we present a facile preparation strategy of near infrared (NIR)-responsive gold nanorod/liquid crystalline elastomer (GNR/LCE) composite films exhibiting fascinating re-shapeable and reusable properties. A random side-chain liquid crystalline copolymer containing biphenyl mesogens and cinnamate side groups has been prepared via ring-opening metathesis polymerization (ROMP), with the [2+2] (retro)cycloaddition of cinnamate groups triggered by various wavelength UV light serving as the reversible dynamic crosslinks for the construction of re-shapeable LCEs. The GNR/LCE composite films with uniformly doped monodisperse GNRs demonstrate remarkable photothermal effects and multi-mode NIR-driven macroscopic deformation capabilities. Furthermore, a single-layer dual-phase composite film composed of periodic micro-patterned monodomain (M) and polydomain (P) structures has been fabricated, which is promising for precise localized NIR-responsive actuation and fully photo-controlled LCE composite devices. [ABSTRACT FROM AUTHOR]

Nanostructured materials of various shape and dimension have aroused intensive interests, among which copper(i) sulfide (Cu2S) nanomaterials are of particular prominence. In this work, various nanostructured Cu2S have been facilely prepared via solventless thermolysis, with well-controlled shape and dimension determined by and inherited from the layered structures of the azobenzene-containing single-source copper thiolate mesogenic precursors. The precursors with longer alkyl tails exhibit highly ordered layered liquid crystalline mesophases and retain persistent order up to temperatures beyond the clearing points. Under non-vacuum inert atmosphere or with further elevated temperature, large undulations of the constrained lamellar space result in significantly enhanced diffusion, migration and mass transfer, thus leading to the morphologies changing from one-dimensional (1D) ultrathin nanowires into thickened nanorods then to discrete 2D nanodisks. Based on a variety of modern techniques, especially in situ variable-temperature small angle X-ray scattering (SAXS), an extended universal “layered-precursor to lamellar-nanomaterial” (LPLM) mechanism has been proposed to account for the structural evolution of Cu2S nanomaterials. Our findings provide a novel pathway with clearer mechanism for well-controlled preparation of metal chalcogenides of various dimension and shape. In particular, the ultrathin Cu2S nanowires are anticipated to serve as fascinating semiconducting materials for various promising device applications. [ABSTRACT FROM AUTHOR]

Metal thiolates have aroused intensive interest mainly due to their precursor-based preparation of nanostructured metal or metal chalcogenides. In this paper, a series of azobenzene-containing thiol ligands with different length alkoxy tails and their corresponding silver thiolates AgS–C10H20–Ph–N=N–Ph–OCnH2n+1 with n = 1, 6, 8, 12, have been successfully synthesized, and their thermal properties and phase behavior have been systematically investigated by differential scanning calorimetry (DSC), variable-temperature SAXS/WAXS and temperature dependent FTIR. By introducing azobenzene mesogen for the first time into the silver thiolates, ordered lamellar liquid crystalline mesophases persisting throughout a higher temperature have been achieved derived from their specific orthorhombic crystalline structures, which are in sharp contrast to the micellar or hexagonal columnar mesophases reported for silver alkane thiolates with a longer aliphatic alkyl chain AgSCmH2m+1 (m≥ 12) owing to the interplay of azobenzene mesogen π–π stacking and the inorganic skeleton binding of a Ag–S slab. Furthermore, the intermediate nanoparticles formation and silver nanodisks preparation through an in situ thermolytic reaction based on such mesogenic precursors have been demonstrated in principle. As a kind of functional metallomesogen precursor the silver mesogenic thiolates with persistent ordered lamellar mesophases provide an ideal two-dimensional (2D) confined environment for the investigation of a layered-precursor-to-lamellar-nanomaterial (LPLM) mechanism of solventless thermolysis and the fascinating controlled preparation of variant 2D shaped metal or metal sulfide nanomaterials. [ABSTRACT FROM AUTHOR]