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To investigate the shape and confinementeffects of the terminalsiloxane groups on the self-assembled behavior of molecular arrangementsin hydrogen-bonded (H-bonded) bent-core complexes, four H-bonded bent-corecomplexes S1, P1, C4, and P8with string-, ring-, and cage-like siloxane termini (i.e.,linear siloxane unit −Si–O–Si–O–Si–,cyclic siloxane unit (Si–O)4, and silsesquioxaneunit POSS, respectively) were synthesized and investigated. By X-raydiffraction measurements, different types of SmCG (B8) phases andleaning angles were controlled by the shape effect of the string-and cage-like siloxane termini for S1and P1(with only one arm of H-bonded bent-core), respectively. In addition,the confinement effect of P1, C4, and P8(accompanied by increasing the numbers of attached H-bondedbent-core arms) resulted in higher transition temperatures and thediminishing of mesophasic ranges (even the disappearance of mesophasein P8). Moreover, AFM images showed the bilayer smecticCG phases of S1and P1were aligned to revealhighly ordered thread-like structures by a DC field. By spontaneouspolarization measurements within the mesophasic ranges, S1and P1showed ferroelectric transitions but C4displayed antiferroelectricity. Finally, the electro-optical performanceof B8 phases could be optimized through binary mixtures of S1and P1, and a well aligned modulated ribbon phase couldbe formed via specific molar ratios of the binary mixtures. [ABSTRACT FROM AUTHOR]

A green production process for producing nickel-loaded LaxNa1−xTaO3, using a hydrogen peroxide-water based solvent system (HW-derived), is reported. The H2evolution of the HW-derived sample is about 1.8 times higher than samples made using ethanol as a solvent. The activity of the sample can be further increased 9.3 times by depositing nanosized nickel as a co-catalyst on the surface of the La0.02Na0.98TaO3. Possible mechanisms of H2evolution from pure water and from aqueous methanol solutions using nickel in three states (i.e.Ni metal, NiO oxide, and Ni/NiO core/shell)-La0.02Na00.98TaO3, are discussed systematically for the first time. It is clearly shown that the activity of hydrogen generation from pure water is in sequence: Ni/NiO > NiO > Ni, whereas the activity sequence with respect to aqueous methanol is: Ni > Ni/NiO > NiO. Metallic Ni presents the most active sites and favors the formation of hydrogen from aqueous methanol. The Ni in Ni/NiO core/shell induce the migration of photogenerated electrons from the bulk to catalyst surface, while NiO act as H2evolution site and prevent water formation from H2and O2. The recombination is interrupted by the effective capture of the holes by methanol acting as a sacrificial reagent, thereby leading to higher hydrogen evolution. In contrast, the competition between the recombination and the charge-transfer reaction occurs in pure water leading to a possible back reaction between H2and O2on the photocatalyst's surface. The photocatalyst synthesis avoids the use of organic solvents and thereby contributes to the environmentally friendly production of hydrogen. [ABSTRACT FROM AUTHOR]

Giant tetrahedral molecules have sparked significant interest in the past decade due to their unique and diverse supramolecular nanostructures. The longer and bulkier peripheral substituents create deep molecular concavities and thus contribute to the different self‐assembly behaviors compared to the conventional small tetrahedral molecules. In this study, a molecular giant tetrahedra, TetraNDI, was synthesized to investigate the important roles of the molecular concavities in the self‐assembly mechanism. Single‐crystal structural characterizations indicate that the TetraNDI takes its trigonal concavities to form 1D supramolecular columns, and its tetragonal concavities to reach close inter‐columnar packing. The difficulty in occupying the concavities leads to the path‐dependent phase behaviors of the giant tetrahedra. It is also found that the remaining molecular concavities in the supramolecular scaffolds affect the CO2 affinity of TetraNDI. With an understanding of the packing principles of molecular giant tetrahedra, the structure‐property relationships could be better evaluated in the future and might broaden the horizon of porous materials. [ABSTRACT FROM AUTHOR]

We present a breakthrough in the synthesis and development of functional gas-responsive materials as highly potent anticancer agents suitable for applications in cancer treatment. Herein, we successfully synthesised a stimuli-responsive multifunctional material (I-R6G) consisting of a carbon dioxide (CO2)-sensitive imidazole moiety and spirolactam-containing conjugated rhodamine 6G (R6G) molecule. The resulting I-R6G is highly hydrophobic and non- or weakly fluorescent. Simple CO2 bubbling treatment induces hydrophobic I-R6G to completely dissolve in water and subsequently form self-assembled nanoparticles, which exhibit unique optical absorption and fluorescence behaviours in water and extremely low haemolytic ability against sheep red blood cells. Reversibility testing indicated that I-R6G undergoes reversible CO2/nitrogen (N2)-dependent stimulation in water, as its structural and physical properties can be reversibly and stably switched by alternating cycles of CO2 and N2 bubbling. Importantly, in vitro cellular assays clearly demonstrated that the CO2-protonated imidazole moiety promotes rapid internalisation of CO2-treated I-R6G into cancer cells, which subsequently induces massive levels of necrotic cell death. In contrast, CO2-treated I-R6G was not internalised and did not affect the viability of normal cells. Therefore, this newly created system may provide an innovative and efficient route to remarkably improve the selectivity, safety and efficacy of cancer treatment. [ABSTRACT FROM AUTHOR]

The mechanism of the intercalation and the expansion of the interlayer distance of nanoclays due to the penetration of polymeric chains is studied using X-ray diffraction as a function of temperature. Poly(trimethylene terephthalate) (PTT) and poly(trimethylene naphthalate) (PTN) belonging to the polyester family were chosen for the formation of nanocomposites with the layered structure nanoclays. The PTN contains the polymorphism ( α-form and β-form) with respect to the temperature. In case of PTT/nanoclay composites, the relative increase in the intercalation extent is found with increasing the temperature. For PTN/nanoclay composite, the intercalation extent is relatively decreased by increasing the temperature due to the fact that thermodynamically and kinetically the transformation of α- to β-form is favored instead of the expansion of nanoclay's interlayer distance. [ABSTRACT FROM AUTHOR]

Poly(ethylene succinate) (PESu), upon crystallization with a morphology‐modulating diluent and at low degree of supercooling, forms peculiarly novel sector‐face dendritic aggregates. Delicate dissection by various microscopic techniques is used to confirm the unique differences of these two faces in the PESu dendrites. Powerful synchrotron‐source generated X‐ray microbeam analysis is performed to prove without doubt the nature of the single crystals that self‐assemble into these two sectors, respectively. Both microscopy results and 1D/2D wide‐angle X‐ray patterns collectively confirm that one sector‐face of the PESu dendrites is composed all fully flat‐on with the single‐crystal's basal face contacting the substrate and branching growth with mutual perpendicular ≈90° angle intersections; the second face is composed fully edge‐on with the prism face contacting the substrate and growth with mutual oblique 5–30° angle intersections. The growth intersection angles are also proved by the azimuthal angles in 1D and 2D X‐ray patterns. [ABSTRACT FROM AUTHOR]

An experimental technique was established to characterize irradiation-induced volume swelling through a combined utilization of synchrotron radiation-based X-ray diffraction (XRD) and transmission electron microscopy (TEM). 3C–SiC specimens were irradiated by Si 2+ ions (5 MeV) with fluences up to 5 × 10 17 ion/cm 2 at 1000 °C. In order to avoid the accumulation of implanted Si ions in the SiC layer, specific thicknesses of the epitaxy layer and implanted ion energy were chosen. Unresolvable black spot defects were studied by TEM, and the average size and density were calculated. XRD radial scan results of surface (0 0 2), (1 1 1), (0 2 2), (1 1 3), and (2 0 0) including peak shift and asymmetry peak broadening were observed. Different interplanar spacing information of single crystal SiC can be obtained from this XRD measurement method, making it possible to investigate the lattice expansion and volume swelling more precisely. While TEM provided a direct visualization of the microstructures and the interplanar spacing was measured from HRTEM images. It is suggested that irradiation induced point defects and compressive stress from the Si substrate were the cause of anisotropic ( a = b < c ) volume swelling of irradiated 3C–SiC in this study. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the structure of poly(trimethylene terepthalate) (PTT)/monolayer nano-mica (MNM) nanocomposites are investigated by wide angle X-ray diffraction (WAXD), small angle X-ray scattering (SAXS) and scanning electron microscope (SEM). In the PTT nanocomposites, the crystallization induces the segregation of MNM in which three morphologies, including interlamellar, interfibrillar, and interspherulitic segregations, are observed with changing the MNM content. Avrami analysis of isothermal crystallization demonstrates that MNM enhances the bulk crystallization rate in the nanocomposites. Moreover, the non-integral values of Avrami exponent n between 2 and 4 with increasing crystallization temperature indicate the mixed growth and nucleation mechanisms. The analysis of secondary nucleation theory for neat PTT and the PTT nanocomposites exhibit the same regime transition of crystallization behaviour in which the classical transition temperatures of regime I to II and regime II to III take place at 488K and 468K, respectively. The growth rate of spherulites of the PTT nanocomposites is twofold larger than that of neat PTT in regime III, implying that MNM plays an effective role as a nucleating agent, since the addition of MNM enormously reduces the activation energy of nucleation, folding surface free energy and average work of chain folding for PTT nucleation. However, experimental results show that the MNM content below 1wt% is the most effective for nucleation of PTT crystallization. [Copyright &y& Elsevier]

Adenine-functionalized biodegradable polymers can be used to directly exfoliate natural graphite into functionalized graphene nanosheets with excellent conductivity and well-tailorable physical properties. [Display omitted] • A supramolecular graphene-based functional composite was successfully developed. • The adenine-functionalized polymer can control the graphite exfoliation process. • The supramolecular polymer forms lamellar nanostructures on the graphene surface. • The resulting graphene exhibited well-tunable layer number and high conductivity. • This development may enable production of custom-tailored graphene nanosheets. Electrically conductive supramolecular polymer composites, based on a combination of natural graphite and the adenine-functionalized biodegradable oligomer 3A-PCL, are able to directly exfoliate crystalline graphite into highly disordered graphene nanosheets with well-tailored structural and physical properties. Herein, we discover 3A-PCL can self-assemble into well-ordered lamellar nanostructures on the surface of graphite due to the strong affinity between 3A-PCL and graphite, and thus lead to direct exfoliation of graphite into well-suspended graphene nanosheets in an organic solvent. Furthermore, after drying, the resulting graphite/3A-PCL composites exhibit stable thermoreversible phase transition behavior between viscous and elastic states, and the number of graphene layers exfoliated can be controlled by tuning the content of 3A-PCL within the composites. Importantly, these newly developed graphene composites possess a low electrical resistivity of 1.5 ± 0.7 mΩ·cm at a graphite loading of 23 wt%, which is more than an order of magnitude lower than that of pristine graphite. Given the simplicity of the production process, well-tailored physical properties and excellent conductive performance, this development offers a highly efficient process for the fabrication of multifunctional supramolecular graphene nanosheets that holds great potential for conductive device applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanofluorophoric PU films with daisy chains as artificial muscles were produced. • Stretchabilities and toughnesses of MIM-based PU elastomers were much improved. • PU films switched ratiometric PL from blue to yellow-orange colors upon stretching. • Shape memory behaviors of stretched PU elastomers were gained by heating (∼100 °C). The extended and contracted conformations of [c2] daisy chain rotaxanes were introduced in mechano-fluorophoric polyurethane (PU) scaffolds via step-growth polymerizations to obtain distinct mechanical and optical features upon external forces. Particularly, the inherent ductile and stretchable capabilities along with notable toughnesses of PU films containing very low contents of [c2] daisy chain moieties with long-range sliding motions were obviously improved. Furthermore, appealing Förster resonance energy transfer (FRET) behaviors with the optimum energy transfer efficiency ca. 26.02% between blue-emitting tetraphenylethylene (TPE) and yellow-orange-emitting rhodamine derivatives could be acquired in the PU film under tensile conditions, which could be assigned to the incorporation of bi-fluorophoric daisy chain rotaxane into PU frameworks to gain reversible dual fluorescence switching behaviors upon stretching and relaxation processes. Additionally, the stretching deformations of PU films were inspected by X-ray diffraction (XRD) and FTIR techniques for the verification of correlated morphological properties of stretching states in the oriented daisy chain rotaxane-based PU films. Interestingly, impressive shape recovery and reversible ratiometric mechano-fluorophoric fluorescence switching properties of [c2] daisy chain rotaxane-based PU films could be attained upon heating, suggesting potential applications of PU films comprising artificial molecular muscles with glorious mechanical and optical behaviors in advanced polymer networks. [ABSTRACT FROM AUTHOR]

A series of side-chain supramolecular polymer complexes containing proton acceptor triblock copolymer, i.e., poly(4-vinylpyridine)-block-polystyrene-block-poly(4-vinylpyridine) (VSV , i.e., P4VP-PS-P4VP), hydrogen-bonded (H-bonded) with two generations of proton donor bent-core mesogenic dendritic pendants (G1 and G2) were prepared and investigated. These two supramolecular polymer complexes (i.e., VSV/G1 and VSV/G2) were characterized by wide- and small-angle X-ray scattering (WAXS and SAXS), and the formation of a microphase separated smectic A (SmA) structure corresponding to a head-to-head layered arrangement was confirmed. The hierarchical structures within the morphologies of supramolecular polymer complexes were proved not only by the SAXS patterns but also by the transmission electron microscopy (TEM). The novel hierarchical lamellar domains of corresponding tetragonal and hexagonal arrangements in different generations of dendritic proton donors (G1 and G2) were self-assembled with triblock copolymer proton acceptor VSV to induce respective BCC (body-centered cubic) and FCC (face-centered cubic) structures in supramolecular polymer complexes VSV/G1 and VSV/G2. Therefore, the shear alignments of characteristic cylindrical column phase micro-domains were developed for the first time to control the unique hierarchical constructions of functionalized self-assembled bent-core structures by utilization of various generations of dendritic proton donors to be H-bonded with triblock copolymer proton acceptor. Image 1 • Side-chain complex polymers contain a triblock copolymer and dendritic LC pendants. • H-bonded complexes are characterized by wide- and small-angle X-ray scattering. • Supramolecular smectic A structure is formed in a head-to-head layered arrangement. • Tetragonal and hexagonal structures are arranged in hierarchical lamellar domains. • 3D-order BCC and FCC structures are induced in self-assembled bent-core complexes. [ABSTRACT FROM AUTHOR]

As reported in our previous work, banded spherulites of isotactic poly(2-vinylpyridine) (iP2VP) with preferred handedness of twisted lamellae can be formed by the inducement of chiral dopants, i.e. , ( R )- or ( S )-hexahydromandelic acids (HMAs). In the present work, we systematically studied the behaviors of chirality transfer in the crystallization of iP2VP associated with the chiral dopant. As evidenced by the signatures of the split-type Cotton effect of circular dichroism (CD) spectra, the chains of iP2VP exhibit exclusive conformational chirality , i.e. , induced circular dichroism (ICD), due to the complexation of chiral dopants ( configurational chirality ) with the lone-pair electron of the iP2VP. With the same growth axis along the radial direction of the banded spherulites, as indicated by selected area electron diffraction (SAED), the helical sense of the twisted lamellae of the iP2VP with ICD can be driven by the chiral dopants. The handedness of the helical chains remains after crystallization with intrinsic crystalline structure of iP2VP, which was revealed by the corresponding results of CD spectroscopy. As a result, a homochiral evolution from the configurational chirality of chiral dopant to the hierarchical chirality of crystallized iP2VP can be developed through directed crystallization of the iP2VP by chiral HMAs. [ABSTRACT FROM AUTHOR]

Melt-crystallization of syndiotactic polystyrene (sPS) is studied using simultaneous small/wide angle X-ray scattering (SAXS/WAXS). Emergence, intensification, and saturation of WAXS reflections within 120 s at isothermal crystallization temperature T c = 250 °C after quenching from 300 °C illustrate crystallinity development through successive nucleation of instantaneously stabilized crystallites of lateral ( hk 0) coherence length Λ ≈ 75 nm. The corresponding SAXS profiles exhibit increased density heterogeneity due to formation of nanograins; fitting of time-resolved SAXS data with a model of arrayed disks reveals slightly thickened ( l c = 7.4–8.4 nm) disks of radius R ≈ 9 nm and long period L ≈ 19 nm with polydisperse stacking number slowly enhanced from an average of 1.2 to 2.4. The moderate ratio of Λ/ 2 R ≈ 4 indicates imperfect coalescence of nanograins in the lamellar assembly process. More importantly, with successively increased T c from 250 to 260 °C the development of density heterogeneity of SAXS invariant Q inv is found to precede that of the WAXS-determined crystallinity X c increasingly more, suggesting a precursor mesophase with non-crystalline nanograins. Avrami analysis for the developments of X c and Q inv further reveals the same Avrami exponent n ≈ 3, consistent with heterogeneous nucleation of crystallites; the corresponding Avrami rate constant κ 1/n ( T c ) extracted from X c is correlated to the crystal growth rates G ( T c ) described by the Hoffman-Lauritzen theory with a common surface-nucleation rate constant K g . A lateral surface energy σ ≈ 17 mJ m −2 can be deduced on the basis of K g using previously determined fold surface energy σ e ≈ 27 mJ m −2 . Correspondingly, κ 1/n ( T c ) extracted from Q inv is described by a mesophase model proposed by Strobl with a zero-growth temperature of the nanograin mesophase ca. 30 K below the β-crystal melting point of sPS. Together, these results suggest that sPS melt-crystallization proceeds with nucleation of non-crystalline nanograins (SAXS-before-WAXS regime) at the crystal growth front, followed by crystallization of the nanograins with similar kinetics to sustain the growth front. Branching/twisting can occur at the lamellar growth front due to frustrated nanograin alignment, favoring the microscopically observed sheaf-like crystal morphology. [ABSTRACT FROM AUTHOR]

In this study, an ion-irradiated single crystal 3C-SiC under fluences of up to 20 dpa at 400–1350 °C was examined using synchrotron based X-ray diffraction and high resolution transmission electron microscopy. Interstitial clusters, dislocation loops, Frank loops, stacking fault loops, and voids in 3C-SiC were investigated. The high resolution TEM results show that clusters collapsed to {1 1 1} small loops when their size reached few nm with increasing temperature, and gradually develop into Frank loops with an added atomic layer along {1 1 1} at 1000 °C. Interplanar spacing information of single crystal SiC was obtained from synchrotron XRD radial scan measurements. Irradiation-induced volume swelling at 400–1350 °C was measured, and the anisotropic ( a = b < c ) swelling behavior of SiC was confirmed. In addition, humps on the right side of SiC (0 0 2) were observed, which suggested that C + /Si + -Si〈1 0 0〉 and/or C + /Si + -C〈1 0 0〉 dumbbells gave rise to diffuse scattering. [ABSTRACT FROM AUTHOR]

Abstract: Novel Pd/NiO core/shell nanoparticles (NPs) have been synthesized by a simple impregnation method with low temperature processing, in a ‘green’, scalable process using nontoxic chemicals. The cocatalyst consisting of a Pd core and a NiO shell formed simultaneously on the surface of La-doped NaTaO3 photocatalyst. The Pd core both induces migration of photogenerated electrons from the bulk of the La0.02Na0.98TaO3 and transfers electrons to the NiO shell. Without the NiO shell, Pd NPs show negligible H2 production from water splitting, due to the rapid reaction between hydrogen and oxygen on the surface. On the other hand, the NiO shell allows the permeation of hydrogen and enables hydrogen reduction on Pd. The incorporation of NiO shell onto Pd remarkably enhances the photocatalytic performance of La-doped NaTaO3 for hydrogen production from pure water. In addition, the core/shell structure can significantly enhance the stability of Pd during the photocatalytic reaction. Similar concepts could be extended to other applications, where the catalytic activity and stability are of concerns. The formation mechanism of the core/shell photocatalyst is proposed based on the high resolution transmission electron microscopy (HRTEM) images and X-ray absorption near-edge structure (XANES) analyses. [Copyright &y& Elsevier]

Abstract: Through a combination of micro-contact imprinting and block copolymer self assembly, a highly dewetting process of a symmetric diblock copolymer occurs, leading to hierarchical development of microstructures (microdroplets or microterraces) and nanodomains. The process is driven by the macroscopically hexagonal-ordered circular geometry of the PS-grafted pattern on silicon substrates and by solvent annealing in solvent vapors of varied selectivity. We investigate how relief P(S-b-4VP) microstructures adjust their internal nanostructures and microscopic shape on a patterned substrate in response to solvent vapors of varied selectivity. Whereas solvent annealing in THF vapor causes formation of nanosphere-comprised droplets with a hemispherical cap, solvent annealing in chloroform and acetone vapors leads to the development of terraced stacks of parallel-oriented lamellae. Each lamellar layer within the terraced stacks has the thickness of an entire PS-P4VP/P4VP-PS layer. In contrast, three types of relief microstructures, nanosphere-comprised terraces, nanocylinder-comprised droplets and nanolamella-comprised terraces, are found in a dynamic process under DMF vapor. For DMF-annealed terraces, the stacks comprise PS-P4VP lamellar layers and thus the thickness of each PS-P4VP lamellar layer is effectively quantized by a half thickness of one PS-P4VP/P4VP-PS layer. The variances in nanoscale and microscale structures are due to the adaption of stimuli-responsive polymer materials to surrounding environments under the confinement of the patterned substrate. [Copyright &y& Elsevier]

Abstract: Poly(ether-block-amide) (PEBA), commercially known as PEBAX®, nanocomposites filled with organically modified clay (Cloisite 30B) and trisilinolphenyl-polyhedral oligomeric silsesquioxane (tsp-POSS) were prepared by a melt mixing method, respectively. The structures of the nanocomposites were investigated using differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, and in-situ simultaneous small and wide angle X-ray scatterings (SAXS and WAXS) during uniaxial deformation. The FT-IR spectra showed the hydrogen bonding between the fillers and the PEBA which helped to disperse the fillers in the polymer matrix. The crystallinities and mechanical properties of the nanocomposites were improved compared to the neat polymer. Their origins were studied with an in-situ simultaneous SAXS and WAXS technique during the uniaxial deformation. [Copyright &y& Elsevier]

Abstract: The effect of polydispersity on morphology and charge transport in MEH-PPV drop-cast films was investigated using grazing incidence X-ray diffraction and time-of-flight. Removing short chain segments promoted the capability of crystallization resulting in higher hole mobility and non-dispersive transport down to lower temperatures. The slope for the Poole–Frenkel relationship at 298K was increased, and its change with temperature decreased, indicating reduced spatial inhomogeneity. Analysis using Bässler’s Gaussian disorder model, found minimal impact on energy disorder and infinite temperature zero field mobility. A good fit for hopping site separation and spatial disorder was only possible for the lower polydispersity device, suggesting that the lower polydispersity films have less mesoscopic inhomogeneity. [Copyright &y& Elsevier]

Abstract: Crystalline NaTaO3 nanoparticles doped with different concentrations of La3+ have been synthesized via a H2O2-assisted sol–gel route. In this reaction, TaCl5 is dissolved in aqueous H2O2 solution to form a stable transparent Ta-peroxo complex solution. The formation of tantalum-peroxo complexes and their chelation by citric acid enables a better control of crystal growth. X-ray diffraction and scanning/transmission electron microscopy provide useful information about crystallinity and morphology of the samples. The substitution of La3+ ions in the NaTaO3 lattice is verified by crystallographic simulation (CaRIne Crystallography version 3.1). These results indicate La3+ ions occupy the Na+ ions sites, which agrees very well with the experimental data. The optimal content of La3+ ions effectively increases crystallinity without agglomeration, contributing to efficient charge separation and preventing recombination between photogenerated electrons and holes. The highest photocatalytic H2 production of 1.43mmolh−1 is obtained for a 2.0mol% La-doped NaTaO3 sample. The NaTaO3 nanoparticles produced using this facile, environmentally friendly ‘green process’ have better crystallinity, smaller size and higher photocatalytic activity. [ABSTRACT FROM AUTHOR]

Numerous efforts have been attempted to mimic human tongue since years. However, they still have limitations because of damages, temperature effects, detection ranges etc. Herein, a self-healable hydrogel-based artificial bioelectronic tongue (E-tongue) containing mucin as a secreted protein, sodium chloride as an ion transporting electrolyte, and chitosan/poly(acrylamide- co -acrylic acid) as the main 3D structure holding hydrogel network is synthesized. This E-tongue is introduced to mimic astringent and bitter mouth feel based on cyclic voltammetry (CV) measurements subjected to target substances, which permits astringent tannic acid (TA) and bitter quinine sulfate (QS) to be detected over wide corresponding ranges of 29.3 mM-0.59 μM and 63.8 mM-6.38 μM with remarkable respective sensitivities of 0.2 and 0.12 wt%−1. Besides, the taste selectivity of this E-tongue is performed in the presence of various mixed-taste chemicals to show its high selective behavior toward bitter and astringent chemicals. The electrical self-healability is shown via CV responses to illustrate electrical recovery within a short time span. In addition, cytotoxicity tests using HeLa cells are performed, where a clear viability of ≥95% verified its biocompatibility. The anti-freezing sensing of E-tongue tastes at −5 °C also makes this work to be useful at sub-zero environments. Real time degrees of tastes are detected using beverages and fruits to confirm future potential applications in food taste detections and humanoid robots. A hydrogel-based artificial E-tongue was inspired by human tongue sensing mechanism to detect astringency and bitter substances. The self-healing and anti-freezing capabilities of detections at −5 °C were explored in this study. HeLa cell viability was performed to show the biocompatibility of the E-tongue used for sensing. For practical usage, the degrees of astringency and bitterness were detected for real beverages and fruits. [Display omitted] • Self-healable and anti-freezing hydrogel-based E-tongue was synthesized. • Astringency detected in the range of 29.3 mM-0.59 μM with a sensitivity of 0.2 wt%−1. • Bitterness detected over the range of 63.8 mM-6.38 μM with a sensitivity of 0.12 wt%−1. • CV and cytotoxicity tests verify corresponding self-healability and biocompatibility. • Detection of E-tongue tastes at −5 °C also makes it useful at sub-zero environments. [ABSTRACT FROM AUTHOR]

Coaxial core/shell electrospun nanofibers consisting of ferroelectric P(VDF-TrFE) and relaxor ferroelectric P(VDF-TrFE-CTFE) are tailor-made with hierarchical structures to modulate their mechanical properties with respect to their constituents. Compared with two single and the other coaxial membranes prepared in the research, the core/shell-TrFE/CTFE membrane shows a more prominent mechanical anisotropy between revolving direction (RD) and cross direction (CD) associated with improved resistance to tensile stress for the crystallite phase stability and good strength-ductility balance. This is due to the better degree of core/shell-TrFE-CTFE nanofiber alignment and the crystalline/amorphous ratio. The coupling between terpolymer P(VDF-TrFE-CTFE) and copolymer P(VDF-TrFE) is responsible for phase stabilization, comparing the core/shell-TrFE/CTFE with the pristine terpolymer. Moreover, an impressive collective deformation mechanism of a two-length scale in the core/shell composite structure is found. We apply in-situ synchrotron X-ray to resolve the two-length scale simultaneously by using the small-angle X-ray scattering to characterize the nanofibers and the wide-angle X-ray diffraction to identify the phase transformations. Our findings may serve as guidelines for the fabrication of the electrospun nanofibers used as membranes-based electroactive polymers. [ABSTRACT FROM AUTHOR]

The structural electrode inspired by nacre and ant-nest architectures makes all-solid-state flexible supercapacitors to meet demands for modern wearable devices, moving toward eco-friendly, safe, aesthetic and high performance. [Display omitted] • A eco-friendly, biomimetic and scalable method for a high-efficiency electrode. • Layers- within -networks structure inspired by nacre and ant-nest architectures. • Biomimetic 4.0 V all-solid-state flexible supercapacitor. • Shapeable electrode meets the aesthetic appeal for fashionable electronics. To meet future demands for cutting-edge wearable electronics, flexible supercapacitors must possess many features, such as eco-friendly processing, aesthetic appeal and no health hazards, in addition to have lightweight, robust and excellent cycling stability. We proposed a biomimetic and scalable method to fabricate an all-solid-state flexible supercapacitor (assFSC) using bioinspired clay/polymer nanocomposites and electroplated manganese oxide as electrode materials and a gel electrolyte. Experimental results from X-ray techniques (tomography, scattering and diffraction) showed that the electrode's structure features a 3D ant-nest-like framework composed of 2D nacre-like clay nanosheets, i.e. hierarchical layers- within -networks structure, which is formed via water-evaporation induced self-organization. The shapeable electrodes made by a molding process could, therefore, be used to meet the demands for fashionable, wearable electronics. Accordingly, the structural electrodes exhibit high tensile strength of 62 MPa, Young's modulus of 4.4 GPa, and torsional strength of 165 MPa. Under a large operating potential of 4.0 V, the assFSC exhibited ultrahigh energy density (233.3 W h kg−1 at 2 kW kg−1), ultrahigh power density (125 kW kg−1 at 55.5 W h kg−1), and outstanding static cyclability (<10% loss after 5000 cycles). We also performed a cycle-life test under dynamic deformation and demonstrated that the assFSC had charging and discharging abilities during motion, according to particle applications of wearable electronics. Thus stable and superior electrochemical performance can be attributed to the biomimetic layers- within -networks structure, which not only provided robust framework but also induced 3D conducting networks with increasing ion channels and shortening charge transports. [ABSTRACT FROM AUTHOR]

• We successfully realized an ultrasensitive NO gas sensor using OSC on vertical channel diode, with suitable UV treatment. • After UV irradiation, the response to 1-ppm NO increases from 93% to 233%. • We investigated the UV irradiation and the incorporation of photochromic molecule to modulate the sensitivity and selectivity in OSC gas sensor. In this work, we successfully proposed an organic semiconductor gas sensor on vertical channel design to exhibit an ultra-sensitive response to nitric oxide gas (10 ppb) at room temperature. The effect of ultra-violet (UV) irradiation (λ =365 nm) on sensing performance of solution processed vertical organic diode (VOD) has been investigated. After implementing a simple and low-cost UV treatment, the sensing response of PBDTTT-C-T based NO sensor is significantly enhanced from 93 % to 233 % at 1 ppm. In addition, we also introduced a new strategy to tune the selectivity of organic gas sensors by using photochromic molecule and organic semiconductor blends. With the 1 Wt% spiropyran dopant, the sensor response to ammonia can be considerably suppressed, hence the response ratio between NO and ammonia can be improved from 2.9 to 16.0, indicating an improved selectivity. The proposed ultrasensitive and selective NO gas sensor have great potential for exhaled breath detection (asthma patients) and environmental monitoring. [ABSTRACT FROM AUTHOR]

The impact of additives on the nanoscale structures of spin-cast polymer composite films, particularly in polymer solar cells, is a topic of significant interest. This study focuses on the blend film comprising poly(thieno[3,4- b ]thio-phene- alt -benzodi-thio-phene) (PTB7) and [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM), exploring how additives like 1,8-di-iodo-octane (DIO) influence the film structures spin-cast from chloro-benzene solution. Combined results of specular X-ray and neutron reflectivity, grazing-incidence small- and wide-angle X-ray scattering (GISAXS and GIWAXS), and X-ray photoelectron spectroscopy indicate that DIO could significantly enhance the dispersion of PC 71 BM and reduce composition inhomogeneity in the film. Time-resolved GISAXS-GIWAXS with 100 ms resolution further captures a rapid spinodal decomposition of the mixture within 1 s in the constant-evaporation stage of spin-casting. Further combined with parallel analysis of time-resolved UV-Vis reflectance, these findings reveal that DIO mitigates the spinodal decomposition process by accelerating solvent evaporation, which, in turn, decelerates phase segregation, leading to a nucleation-driven process. These observations provide mechanistic insights into the role of additives in controlling the nanostructural evolution of spin-cast films by altering the kinetics of solvent evaporation and phase separation during the spin-coating process., (© Kuan-Hsun Lu et al. 2024.)

While luminescent stimuli-responsive materials (LSRMs) have become one of the most sought-after materials owing to their potential in optoelectronic applications, the use of earth-scarce lanthanides remains a crucial problem to be solved for further development. In this work, two manganese-based LSRMs, ( R )-(+)-1-phenylethylammonium manganese bromide, (R-PEA) 2 MnBr 4 , and ( S )-(-)-1-phenylethylammonium manganese bromide, (S-PEA) 2 MnBr 4 , are successfully demonstrated. Both (R-PEA) 2 MnBr 4 and (S-PEA) 2 MnBr 4 show a kinetically stable red-emissive amorphous state and a thermodynamically stable green-emissive crystalline state at room temperature, where the fully reversible transition can be done through melt-quenching and annealing processes. Based on this property, a reusable manganese-halide-based time-temperature indicator is demonstrated for the first time. Furthermore, an X-ray scintillator with a low limit of detection (18.1 nGy/s) and a high spatial resolution limit (30.0 lp/mm) are achieved by exploiting the high transparency of amorphous states. These results uncover the multifunctionality of manganese halides and pave the way for upcoming research.

Integrating structural colors and conductivity into aqueous inks has the potential to revolutionize wearable electronics, providing flexibility, sustainability, and artistic appeal to electronic components. This study aims to introduce bioinspired color engineering to conductive aqueous inks. Our self-assembly approach involves mixing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with sulfonic acid-modified polystyrene (sPS) colloids to generate non-iridescent structural colors in the inks. This spontaneous structural coloration occurs because PEDOT:PSS and sPS colloids can self-assemble into core-shell structures and reversibly cluster into photonic aggregates of maximally random jammed packing within the aqueous environment, as demonstrated by small-angle X-ray scattering. Dissipative particle dynamics simulation confirms that the self-assembly aggregation of PEDOT:PSS chains and sPS colloids can be manipulated by the polymer-colloid interactions. Utilizing the finite-difference time-domain method, we demonstrate that the photonic aggregates of the core-shell colloids achieve close to maximum jammed packing, making them suitable for producing vivid structural colors. These versatile conductive inks offer adjustable color saturation and conductivity, with conductivity levels reaching 36 S cm -1 through the addition of polyethylene glycol oligomer, while enhanced water resistance and mechanical stability are achieved by doping with a cross-linker, poly(ethylene glycol) diglycidyl ether. With these unique features, the inks can create flexible, patterned circuits through processes like coating, writing, and dyeing on large areas, providing eco-friendly, visually appealing colors for customizable, stylish, comfortable, and wearable electronic devices.

The ability of molecules to move and rearrange in the solid state accounts for the polymorphic transition and stimuli-responsive properties of molecular crystals. However, how the crystal structure determines the molecular motion ability remains poorly understood. Here, we report that a three-dimensional (3D) supramolecular gear network in the green-emissive polymorph 1G of a dialkylamino-substituted anthracene-pentiptycene π-system ( 1 ) enables an unusual bifurcated polymorphic transition into a yellow-emissive polymorph ( 1Y ) and a new green-emissive polymorph ( 1G* ) via 3D correlated supramolecular rotation. The 90° forward correlated rotation causes the molecular conformation between the octyl and the anthracene units to change from syn to anti , the ladder-like supramolecular columns to constrict, and the gear network to disengage. This cooperative molecular motion is marked by the gradual formation of an intermediate state ( 1I ) across the entire crystal from 170 to 230 °C, which then undergoes bifurcated (forward or backward rotation) and irreversible transitions to form polymorphs 1Y and 1G* at 230-235 °C. Notably, 1G* is similar to 1G but lacks gear engagement, preventing its transformation into 1Y . Nevertheless, 1G can be restored by grinding 1Y or 1G* or fuming with dichloromethane (DCM) vapor. This work illustrates the correlation between the crystal structure and solid-state molecular motion behavior and demonstrates how a 3D molecular gear system efficiently transmits thermal energy to drive the polymorphic transition and induce fluorochromism through significant conformational and packing changes.

Alkoxy side chain engineering on the β-position of the thienothiophene units of Y6 derivatives plays a vital role in improving photovoltaic performances with simultaneously increasing open-circuit voltage ( V oc ) and fill factor (FF). In this work, we prepared a series of asymmetric non-fullerene acceptors (NFAs) by introducing alkoxy side chains and phenoxy groups on the state-of-the-art Y6-derivative BTP-BO-4F. For the comparison, 2O-BO-4F with a symmetric alkoxy side chain on the outer thiophene units and BTP-PBO-4F with an asymmetric N -attached phenoxy alkyl chain on the pyrrole ring are synthesized from BTP-BO-4F. Thereafter, we construct four asymmetric NFAs by introducing different lengths of linear/branched alkoxy chains on the β-position of the thienothiophene units of BTP-PBO-4F. The resulting NFAs, named L10-PBO, L12-PBO, B12-PBO, and B16-PBO (L = linear and B = branched alkoxy side chains), are collectively called OR-PBO-series. Unexpectedly, all OR-PBO NFAs exhibit strong edge-on molecular packing and weaker π-π interactions in the film state, which diminish the charge transfer in organic solar cell (OSC) devices. As a consequence, the optimal devices of OR-PBO-based binary blends show poor photovoltaic performances [power conversion efficiency (PCE) = 6.52-9.62%] in comparison with 2O-BO-4F (PCE = 12.42%) and BTP-PBO-4F (PCE = 15.30%) reference blends. Nevertheless, the OR-PBO-based binary devices show a higher V oc and smaller V loss . Especially, B12-PBO- and B16-PBO-based devices achieve V oc over 1.00 V, which is the highest value of Y-series OSC devices to the best of our knowledge. Therefore, by utilizing higher V oc of OR-PBO binary blends, B12-PBO and B16-PBO are incorporated into the PM6:BTP-PBO-4F-based binary blend and fabricated ternary devices. As a result, the PM6:BTP-PBO-4F:B12-PBO ternary device delivers the best PCE of 15.60% with an increasing V oc and FF concurrently.

Intrinsically stretchable conductive self-healable organogels containing poly(lipoic acid), Al 3+ ion, tannic acid, and reduced graphene oxide are produced in this report. These noncovalent networks interlocked through physical (hydrogen and coordination) bonds offered high stretchabilities and mechanical strengths as well as fast self-healing behaviors. The optimum organogel-based sensor showed outstanding pressure sensitivities (0.94 kPa -1 up to 10 and 1.07 kPa -1 for 10-50 kPa) and high strain responses (corresponding gauge factors of 1.1 and 0.4 for 0-50 and 50-100% stretching ratios). This organogel also revealed high stabilities at ambient atmosphere due to the presence of binary solvents of dimethyl sulfoxide and glycerol. Additionally, this stretchable thermistor displayed remarkable two-stage sensitivities of -2.6 and -0.4%/°C ranging over 0-30 and 30-80 °C, respectively. Besides, the signal variations of water droplet addition and removal with different temperatures were recorded by the organogel sensor to elucidate the practical applicabilities as a temperature sensor. Moreover, the organogel was utilized to demonstrate humidity sensing, where individual sensitivities of 0.89 and 0.55 were obtained in the respective relative humidity ranges of 10-30 and 40-90%. In the meanwhile, the sensor device illustrated distinct humidity signals during respiration monitoring of nose and mouth breathing detection. Accordingly, these quad-functional sensor applications in strain, pressure, temperature, and humidity detection enable this gel to act as a promising material for future multifunctional flexible electronics.

Understanding the physicochemical modulation of functional molecules is the primary step in exploring novel stimuli-responsive materials, and preventing the π-π stacking configuration of π-conjugated molecules has been an effective strategy of vapochromic material development, such as of nanoporous frameworks. Nevertheless, the more complicated synthetic strategy should in fact be applied in many circumstances. In this study, we explore a facile supramolecular strategy where the commodity plastic, syndiotactic-poly(methyl methacrylate) ( st -PMMA), is utilized to wrap C 60 to form the inclusion complex. The structural characterization revealed that C 60 s in the st -PMMA supramolecular helix had a lower coordination number (CN = 2) compared to the face-centered-cubic packing of pure C 60 s (CN = 12). Since the st -PMMA/C 60 helical complex has structural flexibility, the π-π stacking structure of C 60 was further interrupted by the intercalation of toluene vapors, and the complete isolation of C 60 in the complex induced the desired vapochromic behavior. Furthermore, the aromatic interaction between C 60 and aromatic solvent vapors enabled the st -PMMA/C 60 inclusion complex to selectively encapsulate chlorobenzene, toluene, etc., and induce the color change. The st -PMMA/C 60 inclusion complex exhibited a transparent film of sufficient structural integrity such that it can still induce a reversible color change after several cycles. As a result, a new strategy has been discovered for the development of novel vapochromic materials via host-guest chemistry.

Self-healing properties, originating from the natural healing process, are highly desirable for the fitness-enhancing functionality of biomimetic materials. Herein, we fabricated the biomimetic recombinant spider silk by genetic engineering, in which Escherichia coli ( E. coli ) was employed as a heterologous expression host. The self-assembled recombinant spider silk hydrogel was obtained through the dialysis process (purity > 85%). The recombinant spider silk hydrogel with a storage modulus of ~250 Pa demonstrated autonomous self-healing and high strain-sensitive properties (critical strain ~50%) at 25 °C. The in situ small-angle X-ray scattering (in situ SAXS) analyses revealed that the self-healing mechanism was associated with the stick-slip behavior of the β-sheet nanocrystals (each of ~2-4 nm) based on the slope variation (i.e., ~-0.4 at 100%/200% strains, and ~-0.9 at 1% strain) of SAXS curves in the high q-range. The self-healing phenomenon may occur through the rupture and reformation of the reversible hydrogen bonding within the β-sheet nanocrystals. Furthermore, the recombinant spider silk as a dry coating material demonstrated self-healing under humidity as well as cell affinity. The electrical conductivity of the dry silk coating was ~0.4 mS/m. Neural stem cells (NSCs) proliferated on the coated surface and showed a 2.3-fold number expansion after 3 days of culture. The biomimetic self-healing recombinant spider silk gel and thinly coated surface may have good potential in biomedical applications.

Hydrophobic nanoparticles (NPs) in water were considered unstable because they lack the repulsive electrostatic interaction and steric effect to prevent aggregation. In this study, porous hydrophobic NPs of two star-shaped giant molecules, POSS-(R) 8 , were found to be stable in water and able to retain their kinetic stability in a wide range of temperatures, pH values, and ionic strengths. Unlike the solid hydrophobic NPs that aggregate even with the negative zeta potential (ζ) induced by surface-structured hydrogen-bonded (SHB) water, the porous morphology of POSS-(R) 8 NPs reduces the entropically driven hydrophobic effect to prevent aggregation. With the porous morphology, the hydrophobic NPs are stable without the hydrophilic or charged surface functional groups and demonstrate good encapsulation capability. The morphological factor of colloids is thus one of the missing pieces in the theory of colloidal stability that extends our understanding of colloidal science.

This paper presents a facile method for fabricating a thin-film sample with a high asymmetry value of induced circularly polarized luminescence (iCPL) (|g lum | = 2.0 × 10 -3 ). The method involves mixing stereoregular poly(methyl methacrylate) (PMMA) and chiral chromophore (2,2,2-trifluoro-1-(9-anthryl)ethanol (TFAE)) to form a complex with a dynamic helical conformation of poly(methyl methacrylate) (PMMA) associated with TFAE via hydrogen bonding. This dynamic helical conformation can be stabilized by the stereocomplexation of a pair of stereoregular PMMA, where the TFAE is sandwiched between a double-helix isotactic PMMA and single-helix syndiotactic PMMA, resulting in a preferential one-handed helical conformation with a high value of iCPL from self-assembly.

Molecular backbone modification, alkyl-chain engineering, and end-group functionalization are promising strategies for developing efficient high-performance non-fullerene acceptors (NFAs). Herein, two new NFAs, named TPQ-eC7-4F and TPQ-eC7-4Cl, are designed and synthesized. Both molecules have linear octyl chains on fused quinoxaline-containing heterocyclics as the central backbone and difluorinated (2F)/dichlorinated (2Cl) 1,1-dicyanomethylene-3-indanone (IC) as the end-group units. The influences of alkyl-chains on fused quinoxaline backbone and different halogenated end-groups on optical, electrochemical, and photovoltaic performances of organic solar cells (OSCs) are studied. In comparison with TPQ-eC7-4Cl, TPQ-eC7-4F exhibits blue-shifted absorptions with higher molar extinction coefficients in the film state as well as in the donor/acceptor (D/A) blend film state and up-shifting lowest unoccupied molecular orbital (LUMO) energy level. As a result, the OSC devices based on the PBDB-T:TPQ-eC7-4F display an outstanding power conversion efficiency (PCE) of 15.83% with a simultaneously increased open-circuit voltage ( V oc ) of 0.85 V, a short-circuit current-density ( J sc ) of 25.89 mA cm -2 , and a fill factor (FF) of 72.20%, whereas the PBDB-T:TPQ-eC7-4Cl-based OSC device shows a decent PCE of 14.48% with a V oc of 0.84 V, a J sc of 24.56 mA/cm 2 , and an FF of 69.77%. To the best of our knowledge, this is the highest photovoltaic performance of PBDB-T-based single-junction binary-OSCs. In comparison, ascribed to the high crystallinity and low solubility of BTP-eC7-4Cl, the corresponding PBDB-T:BTP-eC7-4Cl-based OSC device shows poor photovoltaic performance (PCE of 11.87%). The experimental results demonstrate that fine-tuning the fused quinoxaline backbone with alkyl-chain and end-group functionalization are promising strategies to construct high-performance NFAs for PBDB-T-based single-junction binary-OSCs.

Two-dimensional (2D) Dion-Jacobson (DJ) perovskite solar cells (PSCs), despite their advantage in versatility of n-layer variation, are subject to poor photovoltaic efficiency, particularly in the fill factor (FF), compared to their three-dimensional counterparts. To enhance the performance of DJ PSCs, the process of growing crystals and hence the corresponding morphology of DJ perovskites are of prime importance. Herein, we report the fast nonisothermal (NIT) crystallization protocol that is previously unrecognized for 2D perovskites to significantly improve the morphology, orientation, and charge transport of the DJ perovskite films. Comprehensive mechanistic studies reveal that the NIT effect leads to the secondary crystallization stage, forming network-like channels that play a vital role in the FF's leap-forward improvement and hence the DJ PSC's performance. As a whole, the NIT crystallized PSCs demonstrate a high power conversion efficiency and an FF of up to 19.87 and 86.16%, respectively. This research thus provides new perspectives to achieve highly efficient DJ PSCs.

Transition metal high-entropy oxides (HEOs) are an attractive class of anode materials for high-performance lithium-ion batteries (LIBs). However, owing to the multiple electroactive centers of HEOs, the Li + storage mechanism is complex and debated in the literature. In this work, operando quick-scanning X-ray absorption spectroscopy (XAS) is used to study the lithiation/delithiation mechanism of the Cobalt-free spinel (CrMnFeNiCu) 3 O 4 HEO. A monochromator oscillation frequency of 2 Hz is used and 240 spectra are integrated to achieve a 2 min time resolution. High-photon-flux synchrotron radiation is employed to increase the XAS sensitivity. The results indicate that the Cu 2+ and Ni 2+ cations are reduced to their metallic states during lithiation but their oxidation reactions are less favorable compared to the other elements upon delithiation. The Mn 2+/3+ and Fe 2+/3+ cations undergo two-step conversion reactions to form metallic phases, with MnO and FeO as the intermediate species, respectively. During delithiation, the oxidation of Mn occurs prior to that of Fe. The Cr 3+ cations are reduced to CrO and then Cr 0 during lithiation. A relatively large overpotential is required to activate the Cr reoxidation reaction. The Cr 3+ cations are found after delithiation. These results can guide the material design of HEOs for improving LIB performance., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

The strain-stiffening and self-healing capabilities of biological tissues enable them to preserve the structures and functions from deformation and damage. However, biodegradable hydrogel materials with both of these biomimetic characteristics have not been explored. Here, a series of strain-stiffened, self-healing hydrogels are developed through dynamic imine crosslinking of semiflexible O -carboxymethyl chitosan (main chain) and flexible dibenzaldehyde-terminated telechelic poly(ethylene glycol) (crosslinker). The biomimetic hydrogels can be reversibly stiffened to resist the deformation and can even recover to their original state after repeated damages. The mechanical properties and stiffening responses of the hydrogels are tailored by varying the component contents (1-3%) and the crosslinker length (4 or 8 kDa). A combinatorial system of in situ coherent small-angle X-ray scattering with rheological testing is developed to investigate the network structures (in sizes 1.5-160 nm) of hydrogels under shear strains and reveals that the strain-stiffening originates from the fibrous chitosan network with poly(ethylene glycol) crosslinking fixation. The biomimetic hydrogels with biocompatibility and biodegradability promote wound healing. The study provides an insight into the nanoscale design of biomimetic strain-stiffening self-healing hydrogels for biomedical applications.