Polymer Journal

Kawaguchi, Daisuke

doi: 10.1038/s41428-023-00820-6pmid: N/A

Functional polymers, such as semiconducting polymers and polyelectrolytes, play an essential role in polymeric devices due to their electronic properties. The performance of the devices depends on the properties of carriers within the molecules of functional polymers. Therefore, the carrier properties should be strongly influenced by the structures and physical properties of the films. In addition, an interfacial effect becomes more pronounced once the functional polymers are used in a thin-film state and integrated with other inorganic materials. How the chain packing and mobility affect the carrier properties in a thin film should be clarified to design more developed functional devises. In this focus review, the relationship among the aggregation states, the thermal molecular motion, and the carrier properties of the functional polymers and their interfacial effects are discussed.

Ogoshi, Tomoki

doi: 10.1038/s41428-023-00815-3pmid: N/A

Macrocyclic compounds show highly symmetric structures, making them useful building blocks for the creation of various supramolecular assemblies. The properties of such supramolecular assemblies result from their shape, functionality, and structure. In 2008, we reported a new type of polygonal-shaped macrocycle termed “pillar[n]arenes”. In this Focus Review, based on their polygonal structures, versatile functionality, and host–guest behavior, I present various pillar[n]arene-based supramolecular assemblies that have been investigated over the last 10 years in our group. Based on the versatile functionalization of pillar[n]arenes, continuous and length-controllable discrete one-dimensional channels, two-dimensional sheets, and three-dimensional vesicles have been produced. Bulk-state complexations using liquid and crystalline pillar[n]arenes are also discussed. The functionalization of pillar[n]arenes is also useful for creating functionalized crystals, and such crystals have shown guest-responsive changes in color, state, and water contact angle, as well as serving as reaction media for the spontaneous polymerization of cyclic monomers.

Inaba, Hiroshi

doi: 10.1038/s41428-023-00838-wpmid: N/A

Peptides are versatile molecular tools that can self-assemble and participate in molecular recognition processes. Our group has developed rationally designed peptides that (1) bind to the inside of microtubules and (2) cause light-induced peptide nanofiber growth. This focus review describes the construction of new bio-nanoarchitectures using these peptide-based technologies. A newly developed Tau-derived peptide was used to encapsulate various nanomaterials inside microtubules, thereby modulating the structure and function of the microtubules. Moreover, the propulsion of micrometer-sized spheres driven by light-induced peptide nanofiber growth was accomplished. These methods represent new concepts for bio-nanomaterials that mimic, control and surpass natural systems.

Toda, Tomoyuki; Takamura, Yuki; Takenaka, Katsuhiko

doi: 10.1038/s41428-023-00825-1pmid: N/A

Coordination polymerization of a series of 2-substituted-[3]dendralenes, i.e., phenyl- (P3D), hexyl- (H3D), and trimethylsilyl-substituted [3]dendralenes (TMS3D), was investigated. No polymerization was observed for TMS3D, whereas P3D polymerized by CpTiCl3 as a catalyst and modified methylaluminoxane as an auxiliary catalyst to generate polymers that became insoluble in the process of isolation. Additionally, the coordination polymerization of H3D was conducted using a CpTiCl3/modified methylaluminoxane catalyst to produce polyH3D with mainly a trans-4,6 structure, which differs from that of the polymer obtained via anionic polymerization. The copolymerization of isoprene with H3D was also examined, and it was found that the reaction proceeded in a random fashion.

Matsumoto, Takuya; Yorifuji, Miyabi; Hori, Ryohei; Hara, Mitsuo; Yamada, Norifumi L.; Seto, Hideki; Nishino, Takashi

doi: 10.1038/s41428-023-00832-2pmid: N/A

The postfunctionalization of poly(vinyl alcohol) (PVA) with a hierarchical structure has been challenging because conventional polymer functionalization reactions are performed in homogeneous solution states. In this study, the selective functionalization of PVA was achieved in supercritical carbon dioxide (sc-CO2) through acetylation in the amorphous region only and not in the crystalline region. The crystalline region of PVA was retained in the amorphous-selective acetylated PVA synthesized in sc-CO2. In addition, the oriented structure of the PVA crystallites was maintained even after acetylation of the drawn PVA film in sc-CO2. Moisture adsorption affected the crystalline structure of PVA acetylated in sc-CO2. The acetylated PVA synthesized in sc-CO2 included a larger number of water molecules under humid conditions, and the increase in thickness was smaller than that of randomly acetylated PVA. This reason was the rigid crystalline structure and the sequential hydrophilic PVA units in the PVA acetylated in sc-CO2.

Zhou, Qian; Liu, Bing; Jia, Zhaolei; Gao, Xuejiao; Ba, Xinwu; Zhang, Yuangong; Bai, Libin

doi: 10.1038/s41428-023-00811-7pmid: N/A

The aqueous solution of hyperbranched poly(bis-acrylamide)s (HPEAMs) prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization has a lower critical solution temperature (LCST), which can also respond to HCO3-. However, the phase change mechanism of HPEAMs has not yet been proven. In this paper, N-(2-propionamidoethyl)acrylamide was designed as a monomer and chain transfer agent (CTA), and the corresponding linear polymers, hyperbranched polymers and hyperbranched copolymers were further prepared. Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, ultraviolet‒visible spectroscopy, dynamic light scattering and zeta potential were employed to characterize the structure and phase transition behavior. The results confirmed that the bis-acrylamide unit is hydrophilic and the CTA unit is hydrophobic. The hydrophilic-hydrophobic balance system constructed by the unit of bis-acrylamide and CTA endowed the hyperbranched polybisacrylamide with temperature-responsive behavior, and the carboxyl group in the CTA structural unit is the responsive group that makes it possible to tune the LCST in the presence of HCO3-.

Li, Jixian; Gong, Changjun; Tang, Junkun; Yuan, Qiaolong; Liu, Zuozhen; Huang, Farong

doi: 10.1038/s41428-023-00819-zpmid: N/A

Performing investigations on the structure-property relationship of poly(silane arylether arylacetylene)s (PSEAs) is very important and instructive for designing novel high-performance polymers. In this work, three bifunctional acetylene-terminated triphenyl-ether monomers with either para-acetylene, meta-acetylene or ortho-acetylene, i.e., 1,3-bis(4'-ethynylphenoxy)benzene (pmp-BEPB), 1,3-bis(3'-ethynylphenoxy)benzene (mmm-BEPB) and 1,3-bis(2'-ethynylphenoxy)benzene (omo-BEPB) were synthesized and used to prepare three PSEA resins, namely, pmp-PSEA, mmm-PSEA and omo-PSEA. The PSEA resins were characterized by 1H-nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction analysis, and the properties were explored. The resins possess a wide processing window in the following order: pmp-PSEA < mmm-PSEA < omo-PSEA. The DSC results revealed that pmp-PSEA shows the highest reactivity, followed by omo-PSEA and mmm-PSEA. In the cured networks of the resins, the densities increase in the following order: pmp-PSEA-C < mmm-PSEA-C < omo-PSEA-C. Compared with pmp-PSEA-C, mmm-PSEA-C possesses better mechanical properties with a flexural strength of 66.5 MPa and a flexural modulus of 3.71 GPa. The decomposition temperatures of 5% weight loss (Td5) of pmp-PSEA-C and mmm-PSEA-C are over 530 °C.

Kasai, Masahiro; Ohyama, Keiko; Nishimura, Shin

doi: 10.1038/s41428-023-00824-2pmid: N/A

Polyamide (PA) is a potential candidate for seals or barriers in systems used to supply high-pressure hydrogen gas to fuel cell vehicles. The elastic behavior of the crystalline lattices of PA6 and PA11 was investigated using a wide-angle X-ray diffraction (WAXD) method while applying hydraulic pressure. A linear decrease in the d-spacing followed by rapid recovery to the initial value after depressurization was observed as the pressure increased. We refer to this behavior as ‘the elasticity of the crystalline lattice’ in this paper. The 002 peaks of PA6 and the 010 peaks of PA11 shifted to larger angles as the pressure increased. The sheets of molecular chains that were bonded by hydrogen bonding composed a layered structure along the [002] (PA6) or [010] (PA11) direction via the van der Waals force. For PA6, the inverse of the linear compressibility was 2.85 times larger than the previously reported uniaxial tensile elastic modulus, which suggested that an anharmonic potential between neighboring molecular chains caused this asymmetric elasticity. This result will be valuable as a way to clarify the mechanism of mechanical fatigue due to cyclic pressurization stress during the hydrogen supply procedure.

Ono, Michio

doi: 10.1038/s41428-023-00834-0pmid: N/A

In this study, the nature of the linear thermal expansion of injection-molded isotactic polypropylene (iPP) was investigated by temperature-variable small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) techniques. The analysis of the temperature-variable SAXS data was based on the Strobl-Schneider method, and the results provided the temperature dependence along the lengths of the long periods of the iPP lamellae and amorphous layers. Based on these values, the corresponding coefficient of linear thermal expansion (CLTE) αam for the length of the amorphous layer was obtained. The results of temperature-variable WAXS revealed that the iPP had a monoclinic α-form. In addition, the reflection peak corresponding to each crystal plane in the unit cell shifted with increasing temperature, which indicated that the lattice constants, especially the length of each crystal axis, the a-, b-, and c-axes, varied. The CLTE αa, αb, and αc values corresponding to each a-, b- and c-axis were obtained. Combining αam with αa, αb, and αc and information on the orientation of the iPP crystal, i.e., the mean squared cosine <cos2ωa, b, c> provided the total CLTE αcr+am, which allowed thermal expansion to occur in both crystalline and amorphous layers. The resulting αcr+am was in good agreement with the bulk CLTE. Furthermore, αam /αcr+am was >0.99. The linear thermal expansion of the iPP was governed only by the linear thermal expansion of its amorphous layer.

Nguyen, Ngoc Quang; Ryu, Jungju; Kolekar, Govind; Sohn, Daewon

doi: 10.1038/s41428-023-00827-zpmid: N/A

Modified catechol chitosan was synthesized to examine the intricate connections between Fe(III) and catechol under different pH conditions. The conjugation of the catechol moieties, which determines the structure of the hydrogel, was evaluated by nuclear magnetic resonance spectroscopy and ultraviolet‒visible spectroscopy. The gel formation was well maintained by the dual cross-linking networks of the electrostatic interactions between catechol chitosan solution (CCS) and Fe3+ along with the covalent catechol-coupling-based coordinate bonds. Three pH conditions of 3, 5, and 7 were applied for ethylenediamine tetra-acetic acid (EDTA) treatment as a triggering factor in modifying the uniform hydrogel structure. The hydrogels demonstrated enhanced mechanical strength and cohesiveness at a pH of 5, and rheology analysis was used to determine the storage and loss moduli. Several analysis and characterization techniques were utilized to describe the cross-linking components and confirm the physical properties of the chitosan backbone polymer chain in the modified iron-induced hydrogel frameworks before and after EDTA treatment.