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The "single-crystal" lithium-rich layered oxide (SC-LLO) material is applied for the first time to construct a composite cathode by a co-sintering process for garnet-based high-energy all-solid-state lithium metal batteries, which exhibit the high initial discharge capacity of ∼226 mA h g

Matrix viscoelastic properties have been shown to have important effects on cell functions. However, the conventional culture methods for investigating the influences of viscoelastic properties on cell functions cannot exclude the influence of cell morphology. Therefore, in this study, cell morphology was well-controlled by using micropatterns, and the influences of the viscosity of the cell culture medium on cell functions under controlled cell morphology were investigated. Human bone marrow-derived mesenchymal stem cells (hMSCs) were cultured on circular micropatterns of different sizes and elliptic micropatterns of different aspect ratios to control cell size and elongation. The cells were cultured in viscous media of different viscosities, and their osteogenic and adipogenic differentiation were compared. Viscosity could affect the osteogenic and adipogenic differentiation of hMSCs, and the effect was dependent on cell morphology. High viscosity induced a promotive effect on the osteogenic differentiation and an inhibitory effect on the adipogenic differentiation of large and elongated hMSCs. However, viscosity did not affect the osteogenic or adipogenic differentiation of small hMSCs. The effects were correlated with its influence on the actin filament organization of the hMSCs on the micropatterns. The results provide useful information for controlling stem cell functions and tissue engineering.

As light-conversion agents, traditional organic fluorescent dyes easily suffer from solid-state fluorescence quenching and photooxidation, leading to the deterioration of their application performance. To enhance the fluorescence emission and photostability of light-conversion agents in a doped film, in this paper, some luminogens with a cyanostilbene or a phenanthrenecarbonitrile backbone were designed and synthesized based on aggregation-induced emission (AIE) theory, E/Z isomerization and our previous research results, and were characterized via NMR, HR-MS and single-crystal X-ray diffraction. The experimental results indicate that both Z-oCa and Z-pCa exhibit high-contrast Michael addition reaction activity and intramolecular photocyclization, as well as fluorescence quantum yields in the doped film, but similar E/Z photoisomerization and AIE activity. Besides, E-oCa shows stable configuration in solution, but not for Z-pCa, meanwhile, E-oCa and Z-oCa display different AIE activities. More importantly, C-Ca with a twisted molecular configuration succeeded in avoiding fluorescence quenching induced by intramolecular photocyclization, emitting strong fluorescence in the solid state and the PABT-doped film (PLQY = 0.65). After an intensified UV radiation of 20 h, 94% of the initial intensity is reserved, and emission peaks exhibit tiny shifts. Based on matching excitation and emission maxima (374 nm and 433 nm), high PLQY, excellent photostability and light-conversion quality in the doped film, C-Ca is a potential high-performance light-conversion agent. Finally, light-conversion properties and the intrinsic mechanism are discussed in detail using the UV-vis absorption spectra, fluorescence emission spectra, crystal analysis, the photosynthetic photon flux density, the percentages of different wavelength bands, theoretical calculations and XRD patterns. This work is the first report on a highly efficient light-conversion agent with the phenanthrenecarbonitrile backbone; meanwhile, it contributes considerably to the molecular design of photostable luminogens and basic photochemistry.

The aerobic α-hydroxylation of 2-Me-1-tetralone was investigated in imidazol-based ionic liquids (ILs), where reactions in 1-alkyl-3-methylimidazolium tetrafluoroborates were found to generate considerable products. By correlating the conversion at 2 h with viscosity, relative permittivity and the ET(30) value of ILs, we found that the local polarity in ILs represented by the ET(30) value or the chemical shift of α-proton at the substrate was the critical factor influencing the reaction rate. Furthermore, two-dimensional nuclear Overhauser effect spectroscopy (2D NOESY) was used to characterize the distribution of 2-Me-1-tetralone in ILs. As a result, the mesoscopic structures in ILs were recommended to have crucial influences on the distribution of the substrate in ILs, and the caused local polarity could affect the activation of 2-Me-1-tetralone. These findings revealed the solvent effects of ILs with different structures on the α-hydroxylation of 2-Me-1-tetralone, and may encourage the explorations of more types of aerobic oxidations in ILs.

Pepper seed is one by-product in pepper processing, rich in protein, fat, and fiber, and is a new plant-based protein source. In this paper, the physicochemical and functional properties of pepper seed protein isolates (PSPIs) extracted from pepper meal by pressure-assisted defatting (PAD) and conventional solvent defatting (CSD) were investigated. The yields of SPIs extracted by CSD and PAD were 22.8% and 20.5%, respectively. Compared with the PSPIs obtained by CSD, the solubility, water-holding and oil-holding capacities, and emulsifying and foaming abilities of the PSPIs obtained by PAD were significantly increased by 11.22%, 29.17%, 40%, 160%, and 100%, respectively. Additionally, UV-visible, intrinsic fluorescence and infrared spectroscopic characterization revealed the tertiary and secondary conformation changes of the PSPIs, which might contribute to the improvement of their functional properties. Overall, PAD significantly improved the functional properties of the PSPIs. The PSPIs extracted by this innovative technology would be a new plant protein alternative for food formulations with better functional properties.

Cells are surrounded by an extracellular matrix (ECM), which controls cellular functions through biological or physicochemical cues. In particular, cartilage tissues have abundant ECM that is viscoelastic and provides the necessary signals for the maintenance of chondrocyte activity and metabolism. The influence of ECM stiffness on chondrocyte functions has been broadly investigated using elastic hydrogels. However, it is not clear how viscosity impacts chondrocyte functions. In this study, a biphasic gelatin solution/hydrogel system was established for the three-dimensional culture of bovine articular chondrocytes (BACs) to investigate the influence of gelatin solution viscosity on chondrocyte proliferation, ECM secretion and the maintenance of the chondrocyte phenotype. Gelatin solutions of different viscosities supported chondrocyte proliferation and ECM production. However, the cell morphology, proliferation rate, secreted ECM quantity and gene expression levels were different, and these were dependent on the viscosity of the gelatin solutions. Low-viscosity solutions were more beneficial for proliferation, while high-viscosity solutions were more beneficial for ECM production and the expression of collagen type II and aggrecan. Chondrocytes had a more spread morphology in a low-viscosity gelatin solution than in a high-viscosity gelatin solution. The results suggested that high-viscosity was more beneficial for the maintenance of the chondrocyte phenotype, while low viscosity was more beneficial for cell expansion. Viscosity was demonstrated as one of the key parameters affecting cell morphology, proliferation and phenotype.

The discovery of mechanochromic materials with multicolor conversion has mainly depended on accidents and good fortune until now, but manipulating molecular aggregation modes to achieve polymorphism is highly efficient. To obtain multicolor conversion materials and explore the intrinsic mechanism of polymorphism, TPEB2F and TPEB3F were designed and synthesized based on molecular isomerism and aggregation-induced emission (AIE) theory. Although they have similar solvatochromism and AIE properties, TPEB2F and TPEB3F show a high-contrast polymorphism and mechanochromism in terms of reversibility, fluorescence emission intensity and wavelength shift. Only crystal 2R was obtained for TPEB2F, but four different crystals 3Y, 3R, 3N and 3F exist for TPEB3F in the same solvent environment. Emission maxima of 2R show a 22 nm red shift, and its quantum yield (ΦF) was significantly increased to 0.37 from 0.09 after hard grinding. 3Y provided a maximum redshift (40 nm) and slightly reduced ΦF due to different intermolecular stacking and arrangement compared to the others, while 3N exhibited a remarkable blue shift (48 nm) and emission enhancement by gently grinding. X-ray single crystal analysis indicated that mechanochromism was not only related to intermolecular stacking and arrangement but also to the crystal system, space group and density. Theoretical calculations revealed that 2R, 3Y and 3R have an intramolecular charge transfer effect, and furthermore, the key to the formation of polymorphism mainly depends on the dipole moment of stacked molecular pairs and culture solvents rather than the minimum energy of stacked molecular pairs and the dipole moment of a single molecule. In addition, the by-product was purified and characterized in detail for the first time.

All-solid-state batteries based on inflammable inorganic solid electrolytes can fundamentally solve safety issues, especially for high-energy-density Li-metal anodes. However, the development of all-solid-state Li-metal batteries based on a high-capacity lithium layered oxide material is still hindered by the low utilization efficiency of the cathode. Herein, with interface engineering, LiNi0.6Mn0.2Co0.2O2 micro-sized crystalline grains were introduced to make a composite cathode with interfacial stability, continuous Li+ transport channels, and reduced grain interfaces to improve the utilization efficiency. The solid batteries based on the micro-sized crystalline grain material showed initial charge capacity up to ∼170 mA h g−1, discharge capacity of ∼140 mA h g−1, good rate performances, and outstanding cycling stability. The high utilization efficiency of the cathode highlights a promising choice for constructing a composite cathode by micro-sized crystalline grain materials and shines light on the future application of higher-energy-density layered oxide cathode materials.

Mechanochromic materials usually exhibit different mechanochromic behaviour after being ground, smashed and exposed to ultrasound, however, the inherent mechanisms of these different mechanical stresses have remained elusive until now. In order to unveil the critical factors of mechanochromism, five TPE unit containing difluoroboron beta-diketonate complexes with different alkyl chain lengths were synthesized. The results indicate that the complexes show strong solid state fluorescence emission, remarkable AIE properties and multicolor switching. However, the complexes exhibited irregular mechanochromic behavior upon an increase in the alkyl chain length. Upon grinding, the complexes exhibited red-shifted solid state fluorescence emission, and the degree of the red-shift can be mainly attributed to the initial crystalline emission, which depends on the J-type molecular stacking and electron cloud density distribution. In contrast to what was observed after grinding, ultrasonic treatment and smashing led to a blue-shift in the solid state fluorescence emission, and furthermore, with the former being observed to have a better mechanochromic effect than the latter. Based on detailed crystal analysis, the complexes were found to have a similar J-type stacking but different pore structure or head-to-head stacking, which leads to obvious wavelength shift for TPEDKBF2OMe, TPEDKBF2OBu and TPEDKBF2OHe before/after smashing. For TPEDKBF2ONe, the stacking of the flexible long alkyl chains is prone to being destroyed and keep head-to-head J-type stacking from great change, preventing an obvious hypochromic shift in the fluorescence emission. For the first time, the inherent mechanism of mechanochromism can be attributed to the collapse of J-type stacking under ultrasonic treatment and smashing. In addition, the solid-state fluorescence emission properties and detailed crystal analysis also show that hydrophobic interactions and the nonpolar environment of the long alkyl chain can effectively enhance the solid-state fluorescence emission and insertion of nonpolar small molecules.

The physicochemical properties including melting point, density, viscosity, conductivity, and surface tension as well as spectral properties such as infrared and EPR spectra of the chelate-based ILs [Cnmim][Cu(F6-acac)3] (n = 6, 8, 10, 12, 14) were studied as functions of temperature and chain length. The thermodynamic properties such as the standard molar entropy and crystal energy were estimated by Glasser's theory, the molar enthalpy of vaporization was calculated by Kabo's method, and the ionicity was estimated by the Walden rule. Compared with the common ILs, the chelate-based ILs have larger molecular volume, larger density, smaller crystal energy, poorer ionicity and larger enthalpy of vaporization. The infrared spectra data of the ILs showed a red shift of the C-H bond stretching vibration of the alkyl chain in the cation and the EPR spectra showed that the crystal field of Cu2+ was kept when the chain length was elongated, which indicated the existence of microphase separation in the ILs. This work is helpful in understanding the structure-property relations of chelate-based ILs for further application.

Fluorescence emission properties in the single molecule, crystalline and amorphous state are key factors determining the application fields and scope of luminogens. However, the luminescence efficiency of luminogens is usually inconsistent in these three existing forms. To explore multi-state emission properties and the inherent mechanism of luminogens, and obtain rare mechanical force-induced luminescent enhancement and multicolor switching, three D–A–D (Donor–Acceptor–Donor)-type organic boron complexes containing tetraphenylethylene (TPE) and different aromatic amine units are designed and synthesized. TPEDKBF2DMeA, TPEDKBF2Ca and TPEDKBF2DBeA respectively exhibit aggregation caused quenching (ACQ), AIE and dual-state emission (DSE) fluorescence characters. The orange crystals (Oc) of TPEDKBF2Ca show a twisted molecular configuration and head-to-tail J-type stacking mode, while the red crystals (Rc) of TPEDKBF2Ca form scarce super unit cells with the help of two face-to-face antiparallel dimers and the other four single molecules. TPEDKBF2DBeA adopts an antiparallel head-to-head J-type stacking mode, leading to π–π stacking interactions. The faint fluorescence emission of TPEDKBF2DMeA is attributed to parallel J-type stacking based on theoretical calculations. Additionally, TPEDKBF2Ca, TPEDKBF2DBeA and TPEDKBF2DMeA in turn display reversible multi-color switching, blue-shifted fluorescence emission and remarkable luminescent enhancement, and negligible wavelength shift. Detailed single crystal analyses and theoretical calculations indicate that the molecular stacking mode is the critical factor affecting the optical and mechanochromic properties. Meanwhile, this work demonstrates that aryl amine substituents can tune the multistate emission properties of organic fluorophores, which provides a deep understanding for molecular design of multi-state emitters and mechanochromic materials.

Construction of superhydrophobic surfaces with tunable adhesion force has attracted considerable attention in past decades. Here, we demonstrated an exfoliated surface in non-solvent-coated poly(lactic acid) (PLA) films which exhibited controllable domain morphology containing “face-on”, “edge-on” or “peak-on” nano-/micro-structures. A theoretical understanding revealed that such controllable morphology responded closely to the variation in mixture viscosities at a fixed temperature. Furthermore, the resulting films were highly superhydrophobic with contact angles >150°. In particular, adhesion could be tuned ranging from 144 μN to 62 μN for face-on and peak-on surfaces, respectively, by changing the non-solvent content. This strategy allowed for high-efficiency and high-precision transportation of water microdroplets (1 μL) with a yield of ≤100% on homogeneous surfaces. This approach could aid no-mass-lost fluid transportation for a broad variety of applications in bioengineering and biochips.

Aggregation-induced emission (AIE) is a unique photo-physical phenomenon that has become an emerging and hot research area. It has a wide range of applications due to its excellent luminous properties. In this paper, five compounds and their corresponding light conversion films were prepared based on AIE effects and the thermally activated delayed fluorescence (TADF) phenomenon. Furthermore, ultraviolet conversion, dispersion and photo-physical properties such as UV-vis spectra, fluorescence spectra, and photo stability as well as the mechanical properties of the light conversion films were investigated in detail. The results reveal that triphenylacrylonitrile (TPA) exhibits excellent photo stability and ultraviolet light conversion properties. In addition, the fluorescence emission spectrum of TPA corresponds well with the absorption spectrum of plants in the blue-violet region. In particular, the light conversion film with added TPA also shows enhanced mechanical properties and slightly lower visible light transmittance (3.79%) compared to PVC blank film. Based on the photo stabilities of the five compounds, it can be concluded that the electron-withdrawing cyano group can increase the photo stability of TPA, while carbazole substituents are proved to have an uncertain effect on the rate of photo oxidation, which is attributed to the electron-donating properties of carbazole and increased molecular distortion or rigidity. Finally, it is worth mentioning that this is the first report utilizing AIE-active luminogens (AIEgens) in agricultural light conversion film.

Five twisted donor–π–acceptor cyanostilbene derivatives containing carbazole have been designed and synthesized with high yields. Their emission could be tuned from blue to orange by simply altering electron acceptors (donors). It was found that larger molecular dipole and the Stokes shifts of the donor–π–acceptor dyes could result in bathochromic shifts of absorption and emission. The density functional theory calculations further demonstrated that with the increase of the electron-donating or accepting abilities of the substituents, the energy gaps of the fluorophores gradually decreased, which elucidated the substituent effect of the organic fluorophores on their photophysical properties. Moreover, they exhibit typical intramolecular charge transfer (ICT), aggregation-induced emission (AIE), and crystallization-induced emission enhancement (CIEE) characteristics. Furthermore, the hydrogen- (2a), methyl- (2d) and chlorine-substituted (2e) derivatives exhibit remarkable reversible mechanochromic features (with emission wavelength changes up to 119 nm), while the methoxyl- (2b) and nitryl- substituted (2c) derivatives have no mechanochromic characteristics owing to the fact that they have strong crystallizability. The analysis of the X-ray crystal structure proved that the AIE-, CIEE-active and mechanochromic behavior was associated with the stator–rotor structures, twisted conformations and crystal packing modes. More importantly, the substitution effect of cyanostilbene derivatives would provide an effective way to obtain full-color optoelectronic materials with AIE and mechanochromic properties.

Tetraphenylethylene (TPE) is known for its aggregation-induced emission enhancement (AIEE) effect due to the restriction of intramolecular rotation. Some halogen-substituted fluorophores show interesting luminescent phenomena via C–H⋯halogen interactions. By combining TPE units, a halogen with a difluoroboron β-diketonate fluorophore, three complexes, 2a, 2b and 2c, were designed and synthesized. All of them exhibited intramolecular charge transfer, high fluorescence quantum yields, AIEE characteristics and high-contrast mechanochromism. By either grinding-fuming or grinding–annealing cycles, the pristine state or the original emission color of the three complexes can be almost recovered reversibly. In particular, 2c exhibits spontaneous reversibility after grinding at room temperature. Owing to the effect of halogen (Cl, Br), 2b and 2c show polymorphism-dependent fluorescence (yellow plate-like crystals and green needlelike crystals) and higher contrast than 2a before/after grinding. The maximum fluorescence emission wavelength of 2b and 2c shifts bathochromically 70 nm and 59 nm after grinding, respectively. To reveal the mechanochromic mechanism, a series of tests including powder XRD, fluorescence lifetime, DSC, and solid state UV-visible absorbance were completed. The results indicate that mechanochromism of the complexes can be correlated with the transformation between the amorphous and the crystalline states and metastable state formation after grinding, rather than molecular planarization, excimer or exciplex formation. To the best of our knowledge, this is the first example of no alkyl- or alkoxy-substituted difluoroboron β-diketonate complexes that exhibit reversible mechanochromic luminescence.

A hierarchical nickel shell anchored on silica coated magnetic Fe3O4@SiO2 nanospheres (MNPs) has been designed and constructed, which combines the capacity of effective adsorption of protein bovine hemoglobin (BHb) and selective deletion of BHb from real bovine blood samples. Firstly, –NH2 modified silica/magnetite nanoparticles (Fe3O4@SiO2–NH2) were synthesized by combining a sol–gel method and a refluxing process. The Fe3O4@SiO2–NH2 composites revealed a core–shell structure, and the thickness of the silica shell can be easily adjusted by controlling the amount of ammonium solution. Then, the hierarchical nickel shells were anchored on the surface of Fe3O4@SiO2–NH2 by reducing Ni2+ between the solid Fe3O4@SiO2–NH2 and nickel solution with NaBH4. By taking advantage of the high affinity of Ni2+ on the shell surface toward His-tagged proteins and the fast response toward an assistant magnet, the hetero-nanoparticles can be applied to selectively bind to and magnetically separate BHb from the bovine blood. Significantly, it is expected that this approach can be extended to other bimolecular separation and purification processes.

Correction for ‘AIE-active mechanochromic materials based N-phenylcarbazol-substituted tetraarylethene for OLED applications’ by He Zhao et al., RSC Adv., 2015, 5, 19176–19181.

Multifunctional nanocables were prepared by directly welding superparamagnetic Fe3O4 nanoparticle decorated CNTs and Au nanoparticles together with polydopamine (Pdop) as “glue” in a facile but effective way. Additionally, the size and density of the Au nanoparticles can be easily controlled by different chemical approaches. Moreover, these core–shell nanocables can be a versatile platform for multiple applications.

Tricarbazolyl-tristriazolotriazine, a novel Cu(II)-sensing and selective fluorescent sensor, was designed and synthesised on the basis of the mechanism of photoinduced charge transfer. The synthesised compound exhibits highly sensitive and significant fluorescence decline response towards Cu2+ over other metal ions, with a detection limit of 0.2 μM in THF–H2O (9 : 1, v/v) at neutral pH. Its optical, thermal, electrochemical and morphological properties were studied. The results demonstrate that the compound has high relative fluorescence quantum yield (ΦF = 0.99) in xylene solution, excellent thermal stability (Td = 325 °C, Tg = 99.9 °C), wide energy gap (Eg = 4.09 eV), desirable triplet energy (ET = 2.98 eV) and the highest occupied molecular orbital energy (−5.67 eV). Morphological investigation showed that the compound easily forms ribbon-like microstructures.

Correction for ‘AIE-active mechanochromic materials based N-phenylcarbazol-substituted tetraarylethene for OLED applications’ by He Zhao et al., RSC Adv., 2015, 5, 19176–19181.