Syntrophic interaction occurs during anaerobic fermentation of organic substances forming methane as the final product. H2 and formate are known to serve as the electron carriers in this process. Recently, it has been shown that direct interspecies electron transfer (DIET) occurs for syntrophic CH4 production from ethanol and acetate. Here, we constructed paddy soil enrichments to determine the involvement of DIET in syntrophic butyrate oxidation and CH4 production. The results showed that CH4 production was significantly accelerated in the presence of nanoFe3 O4 in all continuous transfers. This acceleration increased with the increase of nanoFe3 O4 concentration but was dismissed when Fe3 O4 was coated with silica that insulated the mineral from electrical conduction. NanoFe3 O4 particles were found closely attached to the cell surfaces of different morphology, thus bridging cell connections. Molecular approaches, including DNA-based stable isotope probing, revealed that the bacterial Syntrophomonadaceae and Geobacteraceae, and the archaeal Methanosarcinaceae, Methanocellales and Methanobacteriales, were involved in the syntrophic butyrate oxidation and CH4 production. Among them, the growth of Geobacteraceae strictly relied on the presence of nanoFe3 O4 and its electrical conductivity in particular. Other organisms, except Methanobacteriales, were present in enrichments regardless of nanoFe3 O4 amendment. Collectively, our study demonstrated that the nanoFe3 O4 -facilitated DIET occurred in syntrophic CH4 production from butyrate, and Geobacter species played the key role in this process in the paddy soil enrichments.

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Combining extensional rheology with in-situ synchrotron ultrafast x-ray scattering, we studied flow-induced phase behaviors of polyethylene (PE) in a wide temperature range up to 240 °C. Non-equilibrium phase diagrams of crystallization and melting under flow conditions are constructed in stress-temperature space, composing of melt, non-crystalline δ, hexagonal and orthorhombic phases. The non-crystalline δ phase is demonstrated to be either a metastable transient pre-order for crystallization or a thermodynamically stable phase. Based on the non-equilibrium phase diagrams, nearly all observations in flow-induced crystallization (FIC) of PE can be well understood. The interplay of thermodynamic stabilities and kinetic competitions of the four phases creates rich kinetic pathways for FIC and diverse final structures. The non-equilibrium flow phase diagrams provide a detailed roadmap for precisely processing of PE with designed structures and properties.

Herein, we present a new strategy in which highly emissive thermally activated delayed fluorescence (TADF) materials can be obtained from modifying or tuning a non-TADF donor (D)–acceptor (A)-type organic molecule via coordination of the metal ionic fragment. Theoretical calculation and photophysical properties reveal that the D–A-type free ligand emits both weak fluorescence and dual room-temperature phosphorescence, whereas the two Ag­(I) complexes display efficient blue TADF, exhibiting photoluminescence quantum yields nearly 100% in films with short decay lifetimes (τ ≈ 6 μs). This is attributed to the four optimized parameters induced by Ag­(I) coordination: (1) narrow singlet (S1)–triplet (T1) energy gaps (ΔE ST). (2) T1 states have a hybrid local excitation and charge transfer (CT) character, and S1 states have a predominant CT character. Both the parameters facilitate reverse intersystem crossing. (3) Radiative rate constant (k r(S1→S0)) is increased. (4) Molecular rigidity is strengthened. For the first time, this work shows a powerful method to design efficient ligand-centered TADF in Ag­(I) complexes based on the conventional D–A-type molecule, which significantly enriches the chemical space for the development of TADF materials.

The sequence and coupling of intra- and interchain orderings in flow-induced crystallization (FIC) of partially cross-linked isotactic polypropylene (iPP) is studied with in situ Fourier transform infrared spectroscopy (FTIR) and synchrotron radiation X-ray scattering techniques, which reveal that multiscale structural intermediates emerge prior to the onset of crystallization. Upon imposing flow, intrachain conformational ordering or coil–helix transition (CHT) occurs first, which is directly correlated with external stress. As helical content is built up at large strain, density fluctuation happens, and sufficient long helices may result in orientation ordering before FIC. The results demonstrate that stress induced intrachain CHT is the essential structural intermediate in FIC, which can be further coupled with interchain orientation and density providing either helical content or length meets the criterions for the phase transitions. We propose that coupling among external stress, intrachain conformational, and interchain orientation and density orderings to be the molecular mechanism for FIC of polymer forming helical structures.

Stretch-induced crystallization (SIC) and phase transitions of poly­(dimethylsiloxane) (PDMS) have been studied with the in situ synchrotron radiation wide-angle X-ray scattering technique (WAXS) during tensile deformation at temperatures ranging from −45 to −65 °C. The phase transitions during tensile deformation go through different processes at different temperature regions, where four phases are involved in namely oriented amorphous (OA), mesophase, α form, and β form crystals. We found that SIC of the α form can proceed via two different multistage ordering processes with either the mesophase or β form as the structural intermediate. Further cyclic tensile experiments demonstrate that the transition from the β to α form is a reversible process controlled by stress, which is attributed to the different helical pitches in β and α forms. A nonequilibrium phase diagram of SIC and phase transitions are constructed in strain–temperature space, which is of great significance for practical applications of PDMS at low temperature.

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