Polymer Journal

Ishiwari, Fumitaka; Shoji, Yoshiaki; Martin, Colin J.; Fukushima, Takanori

doi: 10.1038/s41428-024-00920-xpmid: N/A

Triptycene, a rigid propeller-shaped molecule, was first synthesized in the early 1940s. More recently, many triptycene-containing polymers and molecular assemblies have been developed for a wide range of applications, including guest recognition, material transport, separation, catalysis, and as device components. The advantages of triptycenes lie in their ability to introduce a variety of functional groups on their three-dimensional backbone, with changes in substitution patterns as well as the type of substituents present having a significant impact on the material properties. In this review, we describe the synthesis of triptycene derivatives and polymers, detailing selected examples of triptycene-containing functional polymers. We also focus on the construction of triptycene-based two-dimensional assemblies and polymers, where space-filling designs based on rigid propeller-shaped skeletons are essential. Through a thorough literature survey, future directions and possibilities for the development of triptycene-containing functional materials are discussed.

Mahmoud, Neimatallah Hosni Mohammed; Takagi, Hideaki; Shimizu, Nobutaka; Igarashi, Noriyuki; Sakurai, Shinichi

doi: 10.1038/s41428-024-00919-4pmid: N/A

This study examined the effects of loading amounts of a biobased plasticizer, namely, organic acid monoglyceride (OMG), on the formation of homocrystals (HCs) and stereocomplex crystals (SCs) in PLLA/PDLA (50/50) blends by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and polarized optical microscopy (POM) observations. OMG at different concentrations was added to the PLLA/PDLA (50/50) blend from 0.5 to 5% in 0.5% increments. The addition of OMG was found to enhance SC formation while suppressing HC formation in both nonisothermal and isothermal experiments. The total suppression of HC formation and exclusive SC formation was achieved in the specimens with OMG contents higher than 3% after isothermal crystallization at 170 °C for 5 h. This result was confirmed by WAXD measurements of the specimens with 4 and 5% OMG, where only SC diffraction peaks were observed. In addition, the degree of crystallinity was found to be the same for the specimens with 0 and 5% OMG crystallized at 170 °C for 5 h. These findings imply that not only did the SC form exclusively but also that the presence of OMG actively accelerated its crystallization.

Yoshida, Toyoshi; Touji, Mei; Takagi, Hideaki; Shimizu, Nobutaka; Igarashi, Noriyuki; Sakurai, Shinichi; Uchida, Makoto; Kaneko, Yoshihisa

doi: 10.1038/s41428-024-00924-7pmid: N/A

The macroscopic mechanical properties of polyamides depend on their microscopic structural properties, such as the crystalline phase, lamellar thickness, and long period, which change depending on the heat treatment conditions. In this study, the relationships between the macroscopic mechanical properties and lamellar structures of polyamide 11 obtained from different heat treatments were investigated. Heat treatments include quench, isothermal, and quench–annealing conditions. Wide-angle X-ray scattering measurements indicated that different crystalline phases formed depending on the heat treatment conditions. Polarized optical microscopy and differential scanning calorimetry revealed spherulite and crystal morphologies that were not spherulite. Small-angle X-ray scattering revealed that the lamellar thickness and long period increased with the heat treatment temperature. With increasing the long period of lamellae, the number of stress transmitters, which are stress transfer factors (entanglements, loop chains, etc.) between lamellae, increases. The lamellar thickness and long period of polyamide 11 were ~1.5 times greater than that of polyamide 6 under similar heat treatment. In uniaxial tensile tests, polyamide 6 specimens heat-treated at high temperatures fractured and did not elongate. Polyamide 11 elongated without fracture. The thick lamellar and long-period structure of polyamide 11 obtained from heat treatments in this study might explain its excellent elongation until the late stage of deformation.

Hashimoto, Yuki; Hase, Amane; Tani, Ayumu; Nishimura, Ryo; Hattori, Yohei; Mayama, Hiroyuki; Yokojima, Satoshi; Nakamura, Shinichiro; Uchida, Kingo

doi: 10.1038/s41428-024-00926-5pmid: N/A

Termite wings are covered with hair shafts and micrasters, which provide it with dual wettability. Although the surface is superhydrophobic for bulk water and large droplets, it is adhesive for microdroplets of water. We mimicked this rough surface by applying a photoinduced crystal growth phenomenon on a photoreactive crystalline surface consisting of two photochromic diarylethene derivatives. This crystalline surface showed dual wettability, but the photoreactive crystalline system was not applicable under daylight. This lack of applicability was apparent because the rough crystalline structures on the surface melted under visible light irradiation. We used soft lithography and transcribed the rough structure of the crystalline film to a stable polycycloolefin polymer (ZEONEX 480) surface. In this case, ultrasonic treatment was indispensable for molding complex structured surfaces. The transcribed surface showed the same characteristics of dual wettability as the crystalline surface.

Cho, Rina; Kamata, Hiroyuki; Tsuji, Yosuke; Fujisawa, Ayano; Miura, Yuko; Ishikawa, Shohei; Sato, Ren; Katashima, Takuya; Sakai, Takamasa; Fujishiro, Mitsuhiro

doi: 10.1038/s41428-024-00921-wpmid: N/A

Endoscopic submucosal dissection (ESD) benefits patients in the early stages of cancer, but it poses various risks of complication. Strategies involving the application of clinically approved products to cover ulcers caused by ESD can reduce these complications, but the fixed nature of their properties limit the understanding of their effects on ulcer healing. This study was focused on Tetra–PEG gel, an innovative hydrogel with controllable physical properties made from a sulfhydryl–maleimide pair. The use of biocompatible polyethylene glycol (PEG) in Tetra–PEG gel may allow for its application as a biomaterial. The aims of our study were to identify the characteristics of a self-solidifying hydrogel for endoscopic application and to develop a new ulcer coating agent for post-ESD treatment. We developed a specialized double-lumen catheter and determined the optimal application conditions of the hydrogel. We examined the hydrodynamic properties of the gelling solutions and elucidated the pressure drop that occurred during device operation. Finally, by considering previous experimental results, we successfully applied the hydrogel to post-ESD ulcers in porcine stomachs. We believed that by further optimizing hydrogels with effectively controlled properties and by continuing to investigate them through animal experiments, we could expand our understanding of the relationships among material and ulcer healing properties and apply this knowledge to clinical applications.

Zhou, Xincheng; Matsumoto, Hikaru; Nagao, Masanori; Hironaka, Shuji; Miura, Yoshiko

doi: 10.1038/s41428-024-00923-8pmid: N/A

In this study, a Pd-polymeric porous immobilized catalyst is prepared for the Suzuki–Miyaura coupling reactions by employing a Bayesian optimization method to optimize the catalyst. This research represents the first endeavor to utilize machine learning for the optimization of polymer-immobilized catalysts and provides a novel perspective on utilizing machine learning for the optimization of complex materials.