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  • The polymer chain morphologies of poly(4-iodostyrene) (P4IS) adsorbed on gold nanoparticles (GNPs) inside a polystyrene matrix were visualized using annular dark-field scanning transmission electron microscopy. The P4IS polymer chains adsorbed on GNPs exhibited a unique morphology wherein 1–2 molecular layers of P4IS surrounded a GNP, and the rest of the P4IS was aggregated at the side of the GNP. Enthalpy gain for the surrounding layer via adsorption and entropy gain for the remaining polymer chains via aggregation was considered the reason why the morphology was preferred.

    • Tomohiro Miyata
    • Yoshiaki Kawagoe
    • Hiroshi Jinnai
    Original Article
  • The drug release behaviors of gelatin hydrogels prepared with polymers in terms of their rheological properties were evaluated. In the oscillatory strain sweep, gelatin/HPMCP hydrogels showed a higher crossover strain (Tan δ = 1) than gelatin and gelatin/Eudragit® hydrogels. Thus, gelatin/HPMCP hydrogels had the property of elastic hydrocolloids and tended to keep the platform compared with other sample hydrogels. As a result, the drug release from gelatin/HPMCP hydrogels was delayed compared with other sample hydrogels at pH 1.2.

    • Satoshi Nogami
    • Kazunori Kadota
    • Yuichi Tozuka
    Original Article
  • The first ultrasoft aqueous lithium-ion batteries with coaxial fiber structures were fabricated with an all-hydrogel design. The all-hydrogel fiber aqueous Li-ion battery exhibited a high specific discharge capacity of 84.8 mAh·g−1 and superior cycling behavior and rate capacity performance. A low Young’s modulus (e.g., 445 kPa) for the battery was achieved by making it entirely from hydrogels, which ensured mechanical compatibility with biological tissues.

    • Jiacheng Wang
    • Tingting Ye
    • Ye Zhang
    Rapid Communication
  • Viscoelastic properties of comb-shaped ring (RC) polystyrenes with different branch chain lengths were investigated. Even for the RC sample with short branches, a plateau of the dynamic modulus G*(ω) was observed, suggesting the intermolecular branch chain entanglement occurred. In the region between the plateau and terminal regions, G*(ω) was observed with a weaker angular frequency dependence than the terminal relaxation. The G*(ω) data were analyzed with two models: the comb-Rouse model, in which the structures of RC molecules are taken into account by graph theory, and the Milner-McLeish model for entangled star-shaped polymers.

    • Yuya Doi
    • Jinya Kitamura
    • Yushu Matsushita
    Original Article
  • Among stimuli-responsive polymers, thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) is the most widely investigated. PNIPAAm-based polymers can undergo appropriate changes in response to their external environment. In this focus review, recent advancements in the applications of stimuli-responsive polymers based on PNIPAAm in biomedical fields are summarized, with an emphasis on our own research. In particular, a summary of the design of polymers for application in the separation and purification of (bio)pharmaceutical products and controlled cellular uptake is provided.

    • Yuki Hiruta
    Focus Review
  • The liquid-phase exfoliation of graphite is mass-producible and cost-effective method of graphene production. Polymers can be employed as dispersants to facilitate the exfoliation of graphite in organic solvents. We synthesized methacrylate polymers with various monomer ratios and molecular weights and investigated the efficient acquisition of graphene from graphite. Graphene with a uniform thickness was obtained when graphite was exfoliated using an optimized polymer dispersant.

    • Shimpei Takeda
    • Yuta Nishina
    Rapid Communication
  • The crystalline phase and phase transition behavior of an optically transparent film of star-shaped (heptaisobutyl-T8-silsesquioxy)propyl-substituted octadimethylsiloxy-Q8-silsesquioxane (star-POSS) were studied by DSC and WAXS measurements. This star-POSS exhibited a crystalline phase with a hexagonal system at room temperature and underwent melting above the melting temperature (Tm). The specimens underwent recrystallization even at temperature above Tm, resulting in the same hexagonal system with slightly larger a- and c-axis lengths. The amorphous state of the surrounding isobutyl substituents on the T8-cage framework provides an optically transparent film.

    • Rina Suzuki
    • Lina Li
    • Kensuke Naka
    Original Article
  • We report the nonradiative decay dynamics of charge transfer (CT) states generated in nonfullerene-acceptor-based polymer solar cells. The nonradiative decay rate constants knr decreased with an increase in the efficiency for dissociation of CT states into free carriers, indicating that nonradiative decay of CT states can be mitigated by increasing the delocalization of the CT state wave function.

    • Shin-ichiro Natsuda
    • Toshiharu Saito
    • Yasunari Tamai
    Original Article
  • Asymmetric combinations of chiral 2-hydroxyalkanoic acid (2HAA)-based random copolymers with monomer compositions of approximately 50/50, which can form stereocomplex (SC) crystallites, are reported. The copolymer combinations were l-configured individually crystallizable poly(l-lactic acid-co-l-2-hydroxybutanoic acid) or poly(l-2-hydroxybutanoic acid-co-l-2-hydroxy-3-methylbutanoic acid) and d-configured individually noncrystallizable poly(d-lactic acid-co-d-2-hydroxy-3-methylbutanoic acid). This study strongly suggests that SC crystallization occurred when the common monomer units were incorporated into both l- and d-configured 2HAA-based random copolymers. SC crystallization of new types of asymmetric combinations is expected to diversify the attainable properties and biodegradation behavior of chiral 2HAA-based polymer materials.

    • Hideto Tsuji
    • Katsuya Osanai
    • Yuki Arakawa
    Original Article
  • This review is focused on evolutions of precision radical polymerizations in various directions from metal-catalyzed Kharasch addition or atom transfer radical addition (ATRA). The developments include metal-catalyzed living radical polymerizations via reversible activation of carbon-halogen bonds, metal-catalyzed step-growth radical polymerizations of designed monomers having an unconjugated vinyl group and a reactive carbon-halogen bond, simultaneous metal-catalyzed chain- and step-growth radical polymerization for producing degradable vinyl copolymers with main-chain ester units, and vinyl monomer sequence control via combinations of iterative ATRAs and various controlled polymerizations.

    • Masami Kamigaito
    Review
  • Hetero-telechelic poly(ethylene glycol)s that contain a hydroxy group and a maleimide-furan adduct their α and ω ends, respectively, were isolated as a novel type of hetero-telechelic polymers (HTPs) via the post-modification of commercially available hydroxy-terminated PEGs with furan-protected p-maleimidophenyl isocyanate and subsequent purification with reversed-phase column chromatography at critical conditions.

    • Tatsuki Sato
    • Rikito Takashima
    • Hideyuki Otsuka
    Original Article
  • We report a thermally cross-linkable fluorescent polymer and its assembly to insoluble microbeads by hydrothermal annealing. A novel fluorene-based poly(triarylamine) bearing crosslinkable styryl groups on a fluorene unit is newly designed and synthesized by a Pd-catalyzed amination reaction. The polymer self-assembles into spherical microparticles and becomes insoluble to organic solvents by hydrothermal crosslinking without losing the spherical morphology. Mixing of the polymer with polystyrene enhances the photoluminescence quantum yield by suppressing the aggregation induced quenching and induces a spectral shift of the emission band to green and red after annealing.

    • Yuta Ihara
    • Hiroshi Yamagishi
    • Yohei Yamamoto
    Original Article
  • The addition of rGO affected the molecular and crystalline structures of electrospun PLLA scaffolds, leading to the enhanced piezoresponse. An increase of rGO content up to 1 wt% resulted in the increased number of polar C=O functional groups at the surface of fibers and degree of crystallinity of scaffolds. The maximum increase of the effective local lateral piezoresponse (13.9 pm/V) was achieved for 0.2 wt% rGO doping, which is explained by the presence of the shear piezoelectric α-phase (P212121) in uniaxially oriented PLLA fibers and C=O bond rotation in the polymer chains.

    • Igor O. Pariy
    • Roman V. Chernozem
    • Roman A. Surmenev
    Original Article
  • Optically active polymers and supramolecules that form well-defined architectures are important materials with a wide range of applications. Amino acids and sugars are great candidates for the preparation of optically active functional materials because of their versatile structures and functional groups. In these chiral units, intra- and intermolecular noncovalent interactions play significant roles in the generation of smart functions. In this focus review, the author reviews his recent studies related to the fabrication and functions of chiral conjugated polymers and chiral supramolecules based on these natural chiral compounds.

    • Hiromitsu Sogawa
    Focus Review
  • Tetrazine based one-dimensional organic polymers have been investigated as sensing materials for room-temperature sensing of NO2 gas. The well-defined N-heteroatom functionalization within the polymer’s backbone promotes strong hydrogen-bonding interactions with the analyte and detects various concentrations of NO2 (25–150 ppm). The sensing was also highly selective towards NO2 over other tested analytes such as NH3, EtOH, MeOH, Acetone, 2-nitro toluene, and humidity.

    • Aswani Raj K
    • Guruprasad Gorthala
    • Rajeswara Rao Malakalapalli
    Original Article
  • Multiarmed cyclosiloxanes bearing terminal amine groups (DnA, n = 4, 5) were obtained via a photocatalytic thiol-ene reaction, with regioselectivities of β-adducts as high as 93% irrespective of the repeating unit number in the cyclosiloxane rings. Ketoenamine-linked hybrid networks using D4A and D5A as the starting monomers were successfully synthesized via a mild Schiff base reaction with 2,4,6-triformylphloroglucinol and demonstrated high thermal stability and the formation of nanoparticle assemblies.

    • Huie Zhu
    • Yuhi Watanabe
    • Masaya Mitsuishi
    Original Article
  • Academia and industry are interested in using autotrophic microorganisms as a sustainable/green production platform to produce biochemical products and commercially relevant commodities, including biopolymers. Unlike heterotrophs that require carbohydrates and amino acids for growth, autotrophs have evolved to fix carbon dioxide and drive metabolic processes utilizing either light (photoautotrophs) or chemical compounds (chemolithotrophs) as energy sources. Here, we review the current state-of-the-art in the construction of autotrophic microbial cell factories for efficient biopolymer production and recent breakthroughs in natural autotrophs focusing on biopolymer production.

    • Pisanee Srisawat
    • Mieko Higuchi-Takeuchi
    • Keiji Numata
    Review Open Access
  • Postfunctionalization of aromatic C – H bonds at the main chains of π-conjugated polymers (CPs) is ideal for tuning various functionalities of precursor CPs. In this study, we investigated the electrochemical C – H phosphonylation of the main chain of poly(3-hexylthiophene) (P3HT). Anodic phosphonylation of P3HT was successfully achieved using trialkyl phosphite as an electrically neutral nucleophile in the presence of nonnucleophilic dopants. The chemical structures and the optoelectronic properties of phosphonylated P3HT were characterized. The introduction of phosphonate moieties into the main chain of CPs is potentially useful for improving their processibilities and imparting sensing abilities to them.

    • Kohei Taniguchi
    • Tomoyuki Kurioka
    • Shinsuke Inagi
    Original Article
  • Cationic block copolymers consisting of quaternized pyridinium salt and hydrophobic acrylate segments were synthesized and their basic properties as ink dispersants were evaluated. Among all polymers, the copolymer of 4-vinylpyridine and butyl acrylate shows the best properties in rheology and dispersion stability. However, further optimization of molecular design is necessary to achieve suitable redispersion properties as ink dispersants. Through this study, we demonstrated the potential of cationic block copolymers as ink dispersants and the issues that need to be improved for better ink performance.

    • Toshihiro Ohtake
    • Hiroshi Ito
    • Naoyuki Toyoda
    Original Article