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  • Disiloxane-linked decathiophene and dodecathiophene polymers were prepared and their optical properties were examined. Compared with the monosilane-linked congeners reported previously, these polymers showed slightly redshifted absorption and PL bands in solution. Interestingly, the PL bands were redshifted when the spectra were measured in film, and the redshifts became pronounced as the silicon linkers were elongated from monosilane to disiloxane. This is likely due to the enhanced aggregation of the oligothiophene units, reflecting the improved flexibility of the silicon linkers.

    • Joji Ohshita
    • Akiyoshi Ohta
    • Takeharu Haino
  • Time-resolved small-angle X-ray scattering measurements were made for a mixed solution of silica nanoparticles (SiNPs) and atelocollagen (AC) in aqueous media. The scattering intensity from the SiNPs gradually changed and reached asymptotic values approximately 5–20 min after rapid mixing of the two solutions. The obtained time scale to form the complex can be important information to control the aggregating structure of SiNPs with the aid of collagen molecules.

    • Mari Otsubo
    • Ken Terao
  • We developed lanoconazole (LCZ)-loaded emulsions stabilized with cellulose nanocrystals grafted with polyphosphoesters (LCZ-loaded CP-PEs). The sustained release of LCZ and superior skin permeation of the LCZ-loaded CP-PEs, likely due to the excellent stability and rigidity of oil droplets, assured prolonged local action. The anti-inflammatory efficacy of the LCZ-loaded CP-PEs was confirmed using a mouse ear model of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation.

    • Suphatra Hiranphinyophat
    • Akihisa Otaka
    • Yasuhiko Iwasaki
  • We prepared monolayer- and bilayer-type AuNP-containing collagen coatings as a photosensitive cell scaffold in a photoinduced in situ cell detachment system. The monolayer type of AuNP/collagen coatings showed efficient cell detachment with cell damage and may be applied to remove undesired cells. The bilayer-type AuNP/collagen coatings may be applied to collect desired cells because of the low cell damage. We demonstrated the sorting of visually changed transfected CHO-K1 cells and human-induced pluripotent stem cell-derived cardiomyocytes using our system, which is useful for genome editing and regenerative medicine, respectively.

    • Chie Kojima
    • Anri Kanetsuki
    • Tatsuya Shimizu
  • Over the past two decades, intensive efforts have been devoted to the development of group-10 metal catalysts, especially nickel and palladium ligated by unsymmetric bidentate ligands aimed at the copolymerization of olefins with polar monomers. Here we synthesized a palladium complex bearing a methoxyethoxygroup and applied it to the copolymerization of ethylene and methyl acrylate. Higher incorporation of methyl acrylate was detected in the presence of lithium borate such as LiBArF4. The effect was limited to lithium, and the counteranion also affected the catalyst performance.

    • Shumpei Akita
    • Kyoko Nozaki
  • In this Note, the heat-proofing and anti-plasticizing nature of poly(ethylene carbonate) by the addition of a defibered plant (DP) is presented. The DP was obtained via simple wet-milling treatment for water-dispersed Japanese cedar. The presented results encourage us to use plants as functional fillers without a special chemical/biological reaction.

    • Kazuhiro Shikinaka
    • Ai Tsukidate
    • Yuichiro Otsuka
  • Catalytic ester-interchange reactions allow new sequence information to be written statistically into poly(ester-imide) chains based on NDI (1,4,5,8-naphthalenetetracarboxylic diimide) units. Insertion of the cyclic ester cyclopentadecanolide (“exaltolide”) into an NDI-based homopolymer and quantitative sequence exchange between two different homopoly(ester-imide)s are both catalyzed by di-n-butyl tin(IV) oxide. Emerging sequences from these reactions are identified using pyrene-d10 as a “reader molecule” that binds rapidly and reversibly to the NDI residues, and amplifies the separation of 1H NMR resonances associated with different sequences via cumulative aromatic ring-current shielding.

    • Marcus Knappert
    • Howard M. Colquhoun
    Note Open Access
  • A dinuclear Pd(II) complex possessing a cyclic ligand was applied as a coordinative cross-linker of acrylonitrile–butadiene rubber (NBR). Tensile tests revealed that the mechanical properties of the coordinatively cross-linked NBRs were improved compared with those of the original NBR. Increasing the loading amount of the complex enhanced Young’s modulus, tensile strength, tensile strain, and toughness. The cross-linked NBR could be reused with a simple dissolution and drying process, which featured coordinative cross-linking.

    • Koji Yamamoto
    • Hiromitsu Sogawa
    • Toshikazu Takata
  • We report a novel approach of siloxane bond splitting in organosiloxane using mixture of tris(pentafluorophenyl)borane and dimethyl carbonate. In the first part of this note, depolymerization of polydimethylsiloxane by dimethyl carbonate and with the addition of tris(pentafluorophenyl)borane is studied. Reactions are studied at different concentrations of above-mentioned reagents and temperature while the second part of this note represents theoretical calculation results which explain the mechanism of the depolymerization reaction.

    • Iryna Protsak
    • Volodymyr Gun’ko
    • Volodymyr Turov
  • A series of ester-functionalized polythiophenes (P3OETs) with precisely controlled head-to-tail (HT) ratios was synthesized via palladium-catalyzed direct arylation polycondensation (DArP). The ionization potentials and optical bandgaps of P3OETs decreased as their HT ratios increased because of the increased backbone coplanarity and extensive π-electron delocalization. The method of precisely controlling the regioregularity and HT ratio can contribute to the design of new polythiophene derivatives with enhanced electronic functionality.

    • Taiki Menda
    • Tatsuya Mori
    • Takuma Yasuda
  • Poly(γ-glutamic acid) (PGA) is a biopolymer produced by Bacillus spp. via the γ-amide linkages of d- and/or l-glutamate. PgsB, PgsC, and PgsA are the minimum protein set required for PGA production in B. subtilis, and PgsE improves PGA productivity. Analysis by size-exclusion chromatography combined with multiangle laser light scattering revealed that the molecular weight of PGA was Mw = 2,900,000 g mol−1 or predominantly Mw = 47,000 g mol−1 in preparations derived from B. subtilis cells with or without pgsE, respectively. PgsE may be required to increase the apparent molecular weight of PGA.

    • Ken-Ichi Fujita
    • Takashi Tomiyama
    • Toshio Tanaka
  • We prepared the chemically crosslinked, cylindrical thermoresponsive poly(N-isopropylacrylamide) gels with changing the contents of reversible addition-fragmentation chain transfer (RAFT) agent. The environment in the gel was estimated by using a hydrophobic fluorescence probe. While the equilibrium swelling ratios were comparable, the deswelling response became fast as the content of RAFT agent increased with the formation of “bubble pattern”. This result indicates that the PNIPAAm gels prepared by RAFT still have spatial defects. In addition, the cooperative diffusion coefficients in swelling process of the gels prepared by RAFT polymerization were estimated.

    • Tsukuru Masuda
    • Madoka Takai
  • The synthesis of 100% 13C-labelled poly(propylene carbonate) from the completely alternating copolymerization of propylene oxide (rac-PO and R(+)PO) and 13CO2 is reported. The prepared copolymers were shown to be regioselective with predominately head-to-tail (HT) connectivity. The infrared absorption of the polycarbonate in the $$v_{{\mathrm{co}}_{\mathrm{3}}}$$ v co 3 region is red-shifted by 45 cm−1 from the polymer prepared from 12CO2. This shift in frequency allows for the observation of vNO modes of incorporated dinitrosyl metal complexes.

    • Gulzar A. Bhat
    • Marcetta Y. Darensbourg
    • Donald J. Darensbourg
  • The synthesis of a novel conjugated polymer containing fused pyridinium units in its main chain is reported. A precursor polymer possessing pyridine and tetrafluorophenylene moieties was reacted in the presence of Lewis acid additives to promote the intramolecular nucleophilic aromatic substitution (SNAr) reaction. The polymer reaction with BE3-OEt2 gave a product polymer soluble in polar organic solvents, and the successful formation of fused pyridinium ring structures was spectroscopically confirmed. The electrochemical and optical properties of the synthesized polymers were also investigated.

    • Naoki Shida
    • Honoka Nishimi
    • Shinsuke Inagi
  • A nitrile N-oxide-functionalized polypeptide was synthesized by a two-step method involving the combination of ring-opening polymerization of an amino acid N-carboxyanhydride (NCA) monomer using a primary amine initiator containing a nitroalkane group and a subsequent terminal conversion. The formed peptide was fully characterized by NMR, FT-IR, and MALDI-TOF MS measurements. The catalyst-free grafting reaction of the formed functionalized peptide with rubbers containing double bonds was achieved with high efficiency via an environmentally benign process. These results surely contributed to the development of novel peptide-grafted polymers.

    • Hiromitsu Sogawa
    • Shohei Takamatsu
    • Toshikazu Takata
  • In this report, we evaluated the interplay between molecular weight and mass ratio of polymer during development of viscoelastic properties in HA/FmocFF hybrid supramolecular hydrogels. Rheology was the main tool to assess this complex relationship and the kinetics of network formation during self-assembly were correlated with inherent material properties. Formation of long-rang elastic interactions, ductility and plastic flow were strongly dependent on both size and concentration of polymer, providing a convenient application window to tune the flow properties of the hybrid hydrogels according to the intended application.

    • Ali Nadernezhad
    • Leonard Forster
    • Jürgen Groll
  • Chitin nanofibers were prepared from purified crab-shell chitin particles by repeated high-pressure homogenization in water. AFM images showed that the chitin nanofibers had heterogeneous network structures. X-ray diffraction patterns showed that both the crystallinity index and crystal width of the original α-chitin decreased by nanofibrillation. Solid-state 13C-NMR spectra showed that all C6–OH groups had the gauche–gauche conformation. The degree of N-acetylation increased from 0.83 to 0.98 by nanofibrillation, while the weight-average molar masses of the original chitin and chitin nanofibers were 271,200 and 165,500, respectively.

    • Yuko Ono
    • Kota Ogura
    • Akira Isogai
  • Gels containing the medicinal ingredients of licorice were formed by dissolving herbal medicinal plants into a biocompatible zwitterionic cellulose solvent and successive precipitation. The licorice gels gradually released glycyrrhizic acid, the main medicinal ingredient in licorice, within 3 h. Although the licorice gels were mechanically weak, the gel strength was improved just by the addition of cellulose during the preparation of the gels.

    • Chiaki Kodo
    • Kosuke Kuroda
    • Kenji Takahashi
  • Core cross-linked star-shaped poly(N-isopropylacrylamide) (PNIPAAm), which was prepared via an arm-first method by reversible addition-fragmentation chain-transfer polymerization, was shown to exhibit unique thermoresponsive behavior in water. Star polymers with ~20–35 arms with narrow molecular weight distributions apparently had a more hydrophilic nature compared with that of linear PNIPAAm, judging from their thermoresponsive behavior. Most importantly, an aqueous solution of the star PNIPAAm with carboxy ends remained transparent even at 70 °C.

    • Shohei Ida
    • Yuri Toyama
    • Shokyoku Kanaoka