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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]

Two-dimensional, π-conjugated coordination nanosheets (CONASHs) have attracted significant attention because of their potential applications in electronics and electrode materials. However, multilayer stacking induced by π–π interlayer interaction originating from their flat chemical structures shields the metal complex sites and decreases their performance. The triptycene-linker ligands in CONASHs form square-planar complexes perpendicular to the horizontal planes of the nanosheets, and the C–H bonds in the ligand are directed out of the plane. These features prevent π–π interlayer interactions and expose the axial positions of the metal complexes to pores. In this study, 2,3,6,7,14,15-hexaaminotriptycene (HATT) was used as a ligand to synthesize triptycene-bridged bis-(diimino)-nickel complex coordination nanosheets (Ni-HATT) in a film using a gas–liquid interfacial synthesis method. Facile exfoliation into a thin film several nanometers thick with lateral dimensions of a few micrometers was achieved by ultrasonication in isopropanol owing to weakened interlayer interactions. Furthermore, Ni-HATT-modified electrodes prepared by an electrochemical oxidation method exhibited greater hydrogen evolution reaction (HER) electrocatalytic performance than electrodes modified with conventional CONASH composed of a flat-conjugated ligand owing to easy access to the active sites realized by the chemical structure design obtained by the introduction of the HATT ligand. [ABSTRACT FROM AUTHOR]

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, Zn3BHT, into aqueous Cu(II) and Fe(II) solutions. Upon immersion, the Zn centres in insulating Zn3BHT 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. [ABSTRACT FROM AUTHOR]

Because acellular vascular xenografts induce an immunological reaction through macrophage infiltration, they are conventionally crosslinked with glutaraldehyde (GA). However, the GA crosslinking reaction inhibits not only the host immune reaction around the graft but also the graft's enzymatic degradability, which is one of the key characteristics of acellular grafts that allow them to be replaced by host tissue. In this study, we used an 8‐arm polyethylene glycol (PEG) to successfully suppress macrophage infiltration, without eliminating graft degradation. Decellularized ostrich carotid arteries were modified with GA or N‐hydroxysuccinimide‐activated 8‐arm PEG (8‐arm PEG‐NHS), which has a molecular weight of 17 kDa. To evaluate the enzymatic degradation in vitro, the graft was immersed in a collagenase solution for 12 hr. The 8‐arm PEG‐modified graft was degraded to the same extent as the unmodified graft, but the GA‐modified graft was not degraded. The graft was transplanted into rat subcutaneous tissue for up to 8 weeks. Although CD68‐positive cells accumulated in the unmodified graft, they did not infiltrate into either modified graft. However, the GA‐modified grafts calcified, but the 8‐arm PEG‐modified graft did not calcify after transplantation. These data suggested that 8‐arm PEG‐NHS is a promising modification agent for biodegradable vascular xenografts, to suppress acute macrophage infiltration only. [ABSTRACT FROM AUTHOR]

Analysis of nanostructures is of increasing importance with advances of nanotechnology. Embedded nanostructures in thin films in particular are of recent interest. Grazing incident small angle x-ray scattering (GISAXS) has been recognized to be a powerful method to probe such embedded nanostructures; however, quantitative analysis of scattering pattern is not always trivial due to complex refraction and reflection at surface and interfaces. We prepared nanocellular thin films using block copolymer template with carbon dioxide (CO2); CO2 “bubbles” were formed in the CO2-philic block domains. Such nanocellular structures were analyzed by GISAXS and simulated using distorted wave Born approximation (DWBA). Unlike traditional transmission x-ray scattering, GISAXS requires a careful choice of incident angle to analyze the form factor of scatters embedded in a thin film. Nevertheless, the GISAXS measurements under optimized geometry with quantitative calculations using DWBA revealed that the nanocells are spherical and aligned in a single layer of hexagonal lattice and are surrounded by CO2-philic block domains. [ABSTRACT FROM AUTHOR]

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]

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]

The liquid crystalline material of triply fused metalloporphyrin dimmer is prepared by incorporating hydrophilic triethylene glycol chains (TEG) and amphiphilic paraffinic side chains into the copper porphyrin dimmer. This compound forms a liquid crystal column at room temperature with excellent electron transport ability.

A photoconductive liquid crystal (LC) with bicontinuous arrays of densely packed D and A components, tailored from amphiphilic oligothiophene-[C.sub.60] dyad is described. The results have highlighted the crucial role of the amphiphilic design both in structuring and in photoconductivity.