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Two biodegradable polyesters, poly(butylene succinate) (PBS) and poly(butylene succinate‐co‐adipate) (PBSA), were artificially aged in a UV irradiation test chamber, and their photodegradation behaviors investigated. The attenuated total reflection (ATR) infrared (IR) spectra of the initial and UV‐aged samples revealed conformational changes in the tetramethylene sequences of the photoaged PBS and PBSA. The one‐dimensional wide‐angle X‐ray scattering (WAXS) profiles showed that the (110) d‐spacing of the α‐form crystal progressively decreased during UV aging, suggesting that the crystalline polymer chains became arranged more closely along the fiber axis. Accordingly, we conclude that PBS and PBSA transform from their TGTGT to nearly TTTTT conformations upon photoaging. The observed WAXS, small‐angle X‐ray scattering, and IR spectral data suggest that photodegradation preferentially occurs in the amorphous phase of each polymer. The less crystallizable butylene adipate co‐unit enhances the degradability of PBSA, with prolonged photooxidation leading to partial degradation of the crystalline region of the copolymer. This finding is consistent with and may be linked to the higher biodegradability of PBSA compared to PBS. [ABSTRACT FROM AUTHOR]

In an article published in Angewandte Chemie International Edition, Hiroshi Nishihara et al. present a new method for creating lateral heterojunctions in two-dimensional materials. These heterojunctions have rectifying properties and are formed by immersing a coordination nanosheet made from zinc ions and benzenehexathiol into iron and copper salt solutions. This research has implications for utilizing the attractive properties of two-dimensional materials more effectively. The authors of the article include Choon Meng Tan, Naoya Fukui, Kenji Takada, Hiroaki Maeda, Ekaterina Selezneva, Cédric Bourgès, Hiroyasu Masunaga, Sono Sasaki, Kazuhito Tsukagoshi, Takao Mori, Henning Sirringhaus, and Hiroshi Nishihara. [Extracted from the article]

In an article published in Angewandte Chemie, Hiroshi Nishihara et al. present a new method for creating lateral heterojunctions in two-dimensional materials. These heterojunctions have rectifying properties and can be fabricated by immersing a coordination nanosheet made from zinc ions and benzenehexathiol into iron and copper salt solutions. This research has implications for utilizing the attractive properties of two-dimensional materials more effectively. The authors of the article include Choon Meng Tan, Naoya Fukui, Kenji Takada, Hiroaki Maeda, Ekaterina Selezneva, Cédric Bourgès, Hiroyasu Masunaga, Sono Sasaki, Kazuhito Tsukagoshi, Takao Mori, Henning Sirringhaus, and Hiroshi Nishihara. [Extracted from the article]

Nanowhiskers in a colloidal dispersion are known to form chiral nematic liquid crystals (CNLC), as seen in a cellulose nanowhisker or so-called cellulose nanocrystal and chitin nanowhisker. In our related work, we clarified that once the thus-created chitin nanowhiskers with surface modified by chitosan (CTWK-CS) in CNLC phase were wet-spun, we could directly obtain anisotropic microfibers containing the highly ordered CTWK-CS. This drastic structural transformation from CNLC to anisotropic microfibers might relate to several important stages, i.e., stage (i) is the alignment of CTWK-CS initiated by a specific concentration and flow to create aggregation in the CNLC state, stage (ii) is the coagulation of CTWK-CS in CNLC to transform to microfibers, and stage (iii) is the drying of the thus-extruded microfibers to allow CTWK-CS alignment. The present work sets up the experimental systems simulating stages (i) and (iii) to reveal the orientational behavior of CTWK-CS and the structural evolution, respectively, by synchrotron 2D WAXD measurement. In stage (i), the high degree of the parallel alignments of CTWK-CS with the chain axis oriented along the flow direction of the colloidal dispersions confirms that the flow and concentration synergistically controlled CTWK-CS alignment. In contrast, for stage (iii), the poor c -axial orientation of CTWK-CS in as-spun wet microfibers gradually changed to the high degree of c -axial orientation along the fiber direction during drying process, indicating a reorientation of CTWK-CS along with dehydration. The present study declares an in situ observation of the direct wet spinning of nanowhiskers about their remarkable alignments in the sheared colloidal dispersions (stage (i)) and their random-to-high reorientation during the drying process of the as-spun wet microfiber (stage (iii)).

Heterostructures of two-dimensional materials realise novel and enhanced physical phenomena, making them attractive research targets. Compared to inorganic materials, coordination nanosheets have virtually infinite combinations, leading to tunability of physical properties and are promising candidates for heterostructure fabrication. Although stacking of coordination materials into vertical heterostructures is widely reported, reports of lateral coordination material heterostructures are few. Here we show the successful fabrication of a seamless lateral heterojunction showing diode behaviour, by sequential and spatially limited immersion of a new metalladithiolene coordination nanosheet, Zn 3 BHT, into aqueous Cu(II) and Fe(II) solutions. Upon immersion, the Zn centres in insulating Zn 3 BHT are replaced by Cu or Fe ions, resulting in conductivity. The transmetallation is spatially confined, occurring only within the immersed area. We anticipate that our results will be a starting point towards exploring transmetallation of various two-dimensional materials to produce lateral heterojunctions, by providing a new and facile synthetic route., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)