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The selective removal and immobilization of uranyl ions from aqueous solutions is essential for the sustainable development of nuclear energy. Herein, a robust lanthanide‐organic framework material (IHEP‐24) is developed for simultaneous fluorescence sensing, selective adsorption, and photocatalytic reduction of uranium, integrating three different functions in one material. The confined space formed by the coordination assembly of viologen derivative ligands and metal‐oxygen clusters can act as precise recognition sites for uranyl, allowing IHEP‐24 to efficiently detect and capture uranyl ions. In addition, the presence of a viologen‐based radical ligand enables IHEP‐24 to a further photocatalytic reduction of the adsorbed uranyl to amorphous UO2. The mechanisms of adsorption and photocatalysis are revealed by batch experiments, photoelectrochemical characterizations, and theoretical calculations. This study provides a reference for the construction of robust multi‐functional MOF materials and also provides support for the deep removal and immobilization of radionuclides from aqueous solution. [ABSTRACT FROM AUTHOR]

The hierarchical self‐assembly process opens up great potential for the construction of nanostructural superlattices. Precise regulation of self‐assembled superlattices, however, remains a challenge. Even when the primary molecules are precise, the supramolecular motifs (or secondary building blocks) can vary dramatically. In the present work, we propose the concept of unimolecular nanoparticles (UMNPs). The UMNPs act as the supramolecular motif and directly pack into the superlattices. A highly branched giant molecule is presented. We systematically explore its conformations and the superlattice of this giant molecule. Moreover, intriguing complex phases are discovered when blending this UMNP with other conventional giant molecules. These binary mixtures provide direct evidence to support our previously proposed self‐sorting process in the self‐assembly of "soft alloys". The concept of UMNPs offers a unique approach toward more precise regulation of self‐assembled superlattices in soft matter. [ABSTRACT FROM AUTHOR]

The hierarchical self‐assembly process opens up great potential for the construction of nanostructural superlattices. Precise regulation of self‐assembled superlattices, however, remains a challenge. Even when the primary molecules are precise, the supramolecular motifs (or secondary building blocks) can vary dramatically. In the present work, we propose the concept of unimolecular nanoparticles (UMNPs). The UMNPs act as the supramolecular motif and directly pack into the superlattices. A highly branched giant molecule is presented. We systematically explore its conformations and the superlattice of this giant molecule. Moreover, intriguing complex phases are discovered when blending this UMNP with other conventional giant molecules. These binary mixtures provide direct evidence to support our previously proposed self‐sorting process in the self‐assembly of "soft alloys". The concept of UMNPs offers a unique approach toward more precise regulation of self‐assembled superlattices in soft matter. [ABSTRACT FROM AUTHOR]

In this work, phase segregation and localization of PBSU have been investigated with the combination of SAXS and DSC in its blend with PVDF. After stepwise crystallization of PVDF and PBSU, there are double melting peaks of PBSU in DSC and double scattering peaks in SAXS. It has been demonstrated that double peaks can be attributed to the localization of PBSU in interlamellar/interfibrillar region in pre-formed PVDF crystal framework. In the case of low content of PBSU in blend, PBSU is trapped into the interlamellar region of PVDF crystals, resulting in the alternating lamellae crystal of them and the first peak (with low-q) in SAXS. The enhanced confinement effect produces thinner PBSU lamellae, corresponding to the lower melting temperature in DSC. Upon increasing its content in blend, some PBSU segregates in interfibrillar regions in addition to the enrichment in interlamellar regions of PVDF crystal framework. The larger space and higher concentration of PBSU in interfibrillar-regions contribute to periodic lamellae structure of PBSU with higher thickness, which is the reason for the second peak (with high-q) in SAXS and DSC. Our results not only clarify the relationship between localization of PBSU in interlamellar/interfibrillar regions and double peaks in DSC/SAXS, but also provide a novel strategy to detect the interlamellar and interfibrillar segregation of low-Tm component in miscible crystalline/crystalline blend. [ABSTRACT FROM AUTHOR]

Layer-by-layer polyelectrolyte self-assembly, a common method for preparing high-quality ultra-thin films, was employed to direct the self-assembly behavior of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) block copolymer for the first time. Differing from the previous neutral polymer brushes anchored to silicon substrates via chemical modification, polyelectrolyte multilayers (PEMs) were anchored by electrostatic interaction and provided a stable, smooth, and neutral interface. In the present study, PS-b-PMMA was deposited on poly(acrylamide hydrochloride)/poly(acrylic acid) (PAH/PAA) PEMs prepared by layer-by-layer self-assembly to successfully yield vertical nanodomains after thermal annealing. Seven layered PEMs revealed an excellent, smooth surface, with a low roughness of 0.6 nm. The periodic structure with interlamellar spacing of 47 nm was determined by grazing-incidence small-angle X-ray scattering (GISAXS). The morphology of the PS-b-PMMA nanodomains depended on the polyanion-to-polycation concentration ratio, which is related to the interaction between the block copolymer and the substrate. Our results demonstrate that layer-by-layer self-assembly is a helpful method for the phase separation of block polymers and the fabrication of vertical, ordered nanodomains. [ABSTRACT FROM AUTHOR]

Abstract It is an effective strategy to improve the heat resistance of polylactide (PLA) via forming stereocomplex crystals (SCs) in poly(l -lactide) (PLLA)/poly(d -lactide) (PDLA) blend. In this work, pentearythritol (PENTA), which is an environment-friendly polyhydroxy compound for food packaging, is selected to facilitate the SC crystallization and suppress the HC crystallization for HMW PLLA/PDLA blend. Impressively, only 3 wt% PENTA is added, the exclusive SCs with high content (X c,SC = 50%) can be obtained, which exhibits a high promotion efficiency of crystallization of SCs. Interestingly, with PENTA content ascending, the crystallinity of SCs increases drastically first and then in a relatively slow manner. Furthermore, Miscibility with high content of PENTA leads to a relatively looser packing of SC lamella in the blend confirmed by scanning electron microscope (SEM) due to intercalation of PENTA between crystal lamella. The mechanism of how PENTA facilitates the formation of SCs at molecular level is also proposed in this work. Graphical abstract Image 1 Highlights • An exclusive SCs can be efficiently achieved by addition of food-contact additive of PENTA in PLLA/PDLA blend. • The enhanced mix and intermolecular interactions of PLLA and PDLA chains with PENTA results in preferred SC crystallization. • There is an interplay effect of hydrogen bonding interaction and hydrogen bonding network on the formation of SCs. • The spherulite structure of SCs with a loose packing of lamella is observed by SEM for the first time. [ABSTRACT FROM AUTHOR]

Phase separation in donor/acceptor bulk heterojunction (BHJ) significantly affects the exciton dissociation and charge collection in organic solar cells (OSCs). In this work, the dynamics of phase separation in poly[[4,8-bis[(2-ethylhexyl)oxy] benzo[1,2-b:4,5-b′] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno [3,4-b] thiophenediyl]] (PTB7):[6,6]-phenyl C71 butyric acid methyl ester (PC 70 BM) based BHJ is analyzed. Solvent additive diiodooctane selectively dissolves PC 70 BM aggregation to form homogeneous distribution in PTB7 matrix. Quantitative analyses show that the size of PC 70 BM domains decreases from 67 nm to 38 nm with the addition of solvent additive. The vertical phase separation in PTB7:PC 70 BM BHJ was studied by the X-ray photoelectron spectroscopy measurement and its effect on the performance of the regular and inverted OSCs was examined. Compare to the vertical phase separation occurred in the poly(3-hexylthiophene):PCBM system, the homogeneous vertical phase separation observed in the PTB7:PC 70 BM BHJ favors an enhanced exciton dissociation process for attaining high performing OSCs. [ABSTRACT FROM AUTHOR]

Abstract: Small angle X-ray scattering (SAXS) studies were carried out in Shanghai Synchrotron Radiation Facility (SSRF) to study the effect of addition of TiB2 particles on the melt structures of Al-15 wt% Cu. It was found that doping with TiB2 particles could dramatically reduce the sizes of the melt aggregates at temperatures ranging from the melting point to 800 °C. The results show that the aggregates in the Al–Cu melt present mass fractal characteristics and distribution of incompact 3D flocs. [Copyright &y& Elsevier]

Elongated microvoids, internal fibrillar structure, and edge scattering from both surface refraction cause an equatorial streak in small angle X-ray scattering. A model for analyzing the edge scattering of fibers is proposed. Simulation results indicate that the intensity of edge scattering from surface refraction of a cylindrical fiber is strong and makes an important contribution to the equatorial streak. Two factors influence edge scattering intensity. One is the sample-to-detector distance (D); edge scattering intensity increases with increasing D. The equatorial streak becomes weak when D is shortened. The other factor is the refraction index. Edge scattering intensity increases as the real component of the refraction index decreases. In experiment, weak or even no equatorial streaks were found for samples measured in a roughly index-matching fluid. Edge scattering can be eliminated or weakened, and it can be calculated by comparing the intensities of a cylindrical fiber when it is measured in air and in index-matching fluid. The simulation data are basically in agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Polyamide 6 (PA6) with low moisture-sensitivity is realized by blending with poly(ethylene terephthalate) (PET), the crystal structure and morphology formed under high cooling rate and shear stress are also investigated. A pronounced reduction in the maximum water content from 9.7 to 5.6 wt% accompanying the variation of the diffusion coefficient from 1.2 × 10−6 to 5.2 × 10−7 mm2/s with the increasing of PET content is achieved. The dielectric constant decreases from 12.3 to 6.2 (@103 Hz) and the dielectric loss decreases from 0.25 to 0.13 (@103 Hz) with the increasing of PET content. The structural characterization confirms that the hydrogen-bonding interactions between PA6 and PET play a major role in the reduction of moisture-sensitivity of PA6 as well as that the evolution of the polymorphism of PA6 that the high shear stress facilitates the formation of α-form while the high cooling rate promotes the generation of γ-form. Image 1 • The moisture-sensitivity of polyamide 6 is significantly reduced. • Hydrogen-bonding interactions play a crucial role in the low moisture-sensitivity. • The properties of the blends are well preserved under exposure of water. • The structure of the blends under high cooling rate and shear stress is revealed. [ABSTRACT FROM AUTHOR]