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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]

Strain‐induced crystallization (SIC) in natural rubber (NR) near crack tips significantly enhances crack growth resistance, but understanding the interplay between local strain field and crystallization remains challenging due to confined and heterogeneous characteristics. Using micro‐scale digital image correlation (DIC) and scanning wide‐angle X‐ray diffraction (WAXD, with a narrow 10 µm square beam), this study maps local strain tensor properties and SIC in the vicinity of the crack tip and its peripheral zone (≈3 mm × 1 mm area). The analysis reveals a significant correlation between these properties. In the peripheral zone, there is a noticeable deviation of both the principal strain axis and the crystal orientation from the crack opening direction. These deviations are linearly correlated, which indicates that shear strain plays a significant role in determining the crystal orientation. Crucially, the maximum tensile component in the tensor of local principal strains predominantly dictates local crystallinity. This simplicity is attributed to the limited variation in types of deformation within the SIC region, with corresponding to deformations falling between planar and uniaxial stretching. These findings pave the way for predicting crystallinity distribution using solely strain field data, offering valuable insights into the role of SIC in enhancing the crack growth resistance of NR. [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]

The helix‐sense inversions of poly(β‐phenethyl l‐aspartate) (2P) and diblock copolymers (2P‐3P), with 2P and poly(β‐phenylpropyl l‐aspartate) (3P) blocks, were studied in their solid states using synchrotron wide‐angle X‐ray diffraction and small‐angle X‐ray scattering. The characteristic parameters of the π‐helix structure of 2P were directly determined in situ after the helix transition at a high temperature. In the 2P‐3P block copolymers, the main chains of the 3P blocks initially convert from right‐ to left‐handed α‐helices, and then the 2P blocks convert irreversibly from right‐handed α‐helices to left‐handed π‐helices. The chemical structures of the side chains of poly(l‐aspartic acid ester)s significantly affect their helix transition behaviors. [ABSTRACT FROM AUTHOR]

Structural changes during the drawing and shrinking of linear low-density polyethylene (LLDPE) film are analyzed through in-situ X-ray measurements. A synchrotron radiation source enables simultaneous analyses combining small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD). During drawing, the original unoriented SAXS and WAXD patterns transformed into line and spot patterns, indicating the orientation of both lamellar stacking and the molecular axis along the drawing direction. During the subsequent shrinking these patterns are retained, suggesting the tilted lamellar and molecular chains. A possible model for structural changes indicates that tie molecules between lamellae effectively transmit drawing and shrinking stresses, which contributes to desirable actuation properties. [ABSTRACT FROM AUTHOR]