Browse Articles

  • Original Article |

    The organogels, poly(styrene-co-divinylbenzene); PS gel, poly(styrene-co-divinylbenzene-co-vinylpyridine); PS-VP gel, poly(styrene-co-divinylbenzene-co-vinylbenzoic acid); PS-VBA gel, and poly(styrene-co-divinylbenzene-co-styrenesulfonate); PS-SS gel were prepared with limonene by varying concentration of cross-linker and comonomer to control the gels’ properties. The increase of cross-linker improved the mechanical strength. However, it reduced the solubility in limonene, resulting in the decrease of swelling ratio. The cationic gel shows adsorb ability to anionic compound while anionic gel appears the reverse phenomenon. The limonene organogels were used as lipophilic drug storage and controlled release of testosterone by dense of polymer network.

    • Preeyarad Charoensumran
    •  & Hiroharu Ajiro
  • Original Article |

    Hollow and solid fibers made of polyion complexes of chondroitin sulfate C (CS) and chitosan (CHI) were selectively fabricated using a coaxial two-phase microfluidic device. The selective fabrication was successfully achieved only by changing the solvent of the sheath flow that contained CS. Proteins and nanomaterials could be incorporated in both fibers by mixing them in the core flow, CHI-containing solutions. Results suggested the great potentials of microfluidic techniques for preparation of polysaccharide hollow and solid fibers.

    • Kazutoshi Iijima
    • , Shun Ohyama
    • , Kazuya Yuyama
    • , Atsushi Shono
    •  & Mineo Hashizume
  • Note |

    UV light irradiation causes the unexpected structural transition from core–shell to Janus in droplets consisting of a poly(4-butyltriphenylamine) (PBTPA)/poly(methyl methacrylate) (PMMA) blend solution. We obtained a phase-separated structure formed by the evaporation of the solvent from polymer solution droplets dispersed in an aqueous solution containing a surfactant. It was also found that the transition was caused by UV light with a wavelength of 365 nm, which is mainly absorbed by PBTPA, indicating that this phenomenon is triggered by PBTPA.

    • Shu Kikuchi
    • , Shinji Kanehashi
    •  & Kenji Ogino
  • Original Article |

    10,10′-(1,4-Phenylene)bis(5,7,9-decatriynyl N-(butoxycarbonylmethyl)carbamate) 1 and its perfluorophenylene derivative 2 were synthesized. Upon UV irradiation, both of them showed excitonic absorption of polydiacetylene. In particular, 2 showed an absorption maximum at 743 nm, which was approximately 100 nm longer than that of conventional polydiacetylenes, and its solid-state polymerization scheme was investigated.

    • Keita Sasamura
    • , Kei Mizuguchi
    • , Yoko Tatewaki
    •  & Shuji Okada
  • Focus Review |

    The liquid crystalline (LC) rod-like mesogens preferentially orient normal to the substrate plane due to the excluded volume effect (homeotropic alignment) in side-chain liquid-crystal (SCLC) polymers free-standing films. For in-plane alignment, a homeotropic orientation is unsuitable because the mesogens are in a direction opposite to the in-plane directions. This review focuses on new approaches to induce a random planar orientation in SCLC polymer systems by interface and surface molecular design utilizing a high-density polymer brush structure and surface segregation structures of block copolymers.

    • Shusaku Nagano
  • Focus Review |

    Interfacial morphologies and associated processes in multicomponent polymer systems, e.g., block copolymers (BCPs) and polymer blends, are examined using three-dimensional (3D) microscopies. Because of the rich structural information in 3D images, various new types of structural parameters, including chain conformation inside BCPs nanodomains, chain packing frustration in BCPs, Genus etc., can be obtained. The stability and interfacial dynamics are also discussed.

    • Hiroshi Jinnai
  • Focus Review |

    Direct arylation polycondensation has been investigated to develop efficient synthetic methods of conjugated polymers for use in optoelectronic applications. The optimization of reaction conditions achieved high molecular weights and minimal structural defects in the recurring structures. The optimized direct arylation method has several advantages over conventional methods, e.g., fewer synthetic steps, and high-molecular-weight and high-purity polymer. The high-quality polymeric materials exhibited superior performance to those obtained using a conventional method when used in organic photovoltaics and field-effect transistors.

    • Junpei Kuwabara
  • Original Article |

    A palladium (Pd) was confined within poly(N-isopropylacrylamide)-based hydrogel particles (GPs) with different sized hydrogel network. Nanosized Pd was loaded in the GPs via ligation to tertiary amine group in the GPs. The size of gel network was tuned varying the feed ratio of crosslinker. The catalytic efficacies of Pd-loaded GPs were significantly higher than those of commercially available Pd-loaded supports in Suzuki coupling reaction under aqueous condition. Using the smallest gel network, Pd-loaded GPs achieved the highest turnover number for the catalytic reaction, owing to protection of Pd from aggregation.

    • Hikaru Matsumoto
    • , Takanori Akiyoshi
    • , Yu Hoshino
    • , Hirokazu Seto
    •  & Yoshiko Miura
  • Focus Review |

    Flavin catalysts are typically metal-free, and their catalytic activity can be readily accessed using mild terminal oxidants such as H2O2 and O2; therefore, redox reactions with these compounds have great promise as alternatives to reactions with conventional metal catalysts for the sustainable production of important chemicals. Herein, our recent research on flavin catalysts including the development of facile preparation methods for flavin catalysts using polymers, readily reusable polymer-supported flavin catalysts, and flavin-peptide-polymer hybrids that can catalyze the first flavoenzyme-mimetic aerobic oxygenation reactions is summarized.

    • Yukihiro Arakawa
    • , Keiji Minagawa
    •  & Yasushi Imada
  • Original Article |

    The grain size was quantitatively evaluated on the free surface, and in the thickness direction. The grain growth on the free surface was very slow in the early stage of thermal annealing, then it shifted to a rapid mode with a power law (~t0.7). While in the thickness direction, the growth followed a power law of t1.72 until 1180 min, then it shifted to a slow mode with t0.21. Furthermore, the oriented layer near the free surface was found to be as thick as 9.5 µm, indicating that grain growth serves as a propagator for the regular ordering of spherical microdomains and orientation of the bcc lattice.

    • Rasha Ahmed Hanafy Bayomi
    • , Konomi Honda
    • , Isao Wataoka
    • , Hideaki Takagi
    • , Nobutaka Shimizu
    • , Noriyuki Igarashi
    • , Sono Sasaki
    •  & Shinichi Sakurai
  • Focus Review |

    This focus review addresses recent progress on plant oil-based functional polymers and composites. An environmentally benign coating system is demonstrated using plant oils as the starting substrate for the preparation of artificial urushi with high hardness and a high gloss surface. Epoxidized plant oils are polymerized with designed inorganics, cellulose, and biodegradable aliphatic polyesters to afford functional biobased polymers and composites. Castor oil is used as the core of branched poly(lactic acid) to improve the physical properties of biobased plastics.

    • Hiroshi Uyama
  • Original Article | | open

    Nanocomposites containing mesoporous silica (MPS) materials with various pore structures (SBA-15 and MCM-41 types) melt mixed into polypropylene (PP) or PP functionalized with hydroxyl groups (PPOH) were characterized by analytical pyrolysis techniques, such as evolved gas analysis (EGA)-mass spectrometry (MS) and heart-cut EGA-gas chromatography (GC)/MS, to evaluate the interactions between the polymer matrix and MPS and the pore filling of the MPS in the nanocomposite. The EGA-MS measurements revealed that nanocomposites with MPSs evolve specific degradation products, which can be attributed to strong interactions between the polymer molecules and the internal pores. The amount of these specific products increased upon increasing the pore size of the MPS and the hydroxyl content in the polymer matrix. Sufficiently large pores of MPS and high hydroxyl contents in the matrix appear to provide strong interactions because the MPS pores are well-filled with polymer molecules, which contributes to the improved physical properties of the nanocomposites.

    • Ryota Watanabe
    • , Hideaki Hagihara
    •  & Hiroaki Sato
  • Original Article |

    Double helical polysaccharide, xanthan samples with varying molar mass were thermally denatured and renatured in dilute solutions. The molar mass decreased after denaturation and renaturation for samples with an initial molar mass of 106 g mol−1, but those for the samples with an initial molar mass of 105 or 107 g mol−1 decreased only slightly. A model explaining this molar mass dependence of the denaturation and renaturation behaviors was proposed based on the experimental results.

    • Yasuhiro Matsuda
    • , Kazuya Okumura
    •  & Shigeru Tasaka
  • Original Article | | open

    Nanocomposites composed of mesoporous silica (MPS) materials with various porosity structures (two types of SBA-15 with pores of 4.4 or 8.0 nm, and MCM-41 with pores of 2.9 nm and polypropylene (PP) or functionalized PP containing hydroxyl groups (PPOH) were developed. The nanocomposite containing PPOH and SBA-15 with a pore of 8.0 nm showed higher toughness, stiffness, and transparency than the other nanocomposites.

    • Ryota Watanabe
    • , Hideaki Hagihara
    •  & Hiroaki Sato
  • Original Article |

    Random copolymers of l-lactic acid (LLA) and glycolic acid (GA) [P(LLA-GA)] with LLA unit contents in the ranges of 0–20 and 73–100 mol% were crystallizable during precipitation or melt-crystallization. The GA units of the LLA-rich P(LLA-GA) copolymers were incorporated in a lattice of LLA unit segments, whereas the LLA units of the GA-rich P(LLA-GA) copolymers were incorporated in a lattice of GA unit segments. Even the incorporation of relatively small-sized GA units in relatively large-sized LLA unit segments strongly induced structural disorder in the crystalline lattice.

    • Hideto Tsuji
    • , Koudai Kikkawa
    •  & Yuki Arakawa
  • Focus Review |

    Preparation of Polymer Brushes with Well-Controlled Stereoregularity and Evaluation of Their Functional Properties High-density poly(methyl methacrylate) (PMMA) brushes with well-controlled stereoregularity were prepared using a surface-initiated living anionic polymerization method in the presence of a Lewis acid. A molecular weight range from 6 K to 400 K with a narrow polydispersity index (PDI) was obtained. Grazing incidence wide-angle X-ray diffraction measurements indicated that the polymer brushes formed a helical structure approximately 1 nm in diameter and consisting of encapsulated functional molecules or polymers, leading to the formation of inclusion complexes or stereocomplexes.

    • Tomoyasu Hirai
    • , Masanao Sato
    • , Tomoki Kato
    • , Hitoshi Shimamoto
    • , Kiyu Uno
    • , Nobuyuki Otozawa
    •  & Atsushi Takahara
  • Review |

    Among various approaches to create self-healing polymers, the introduction of dynamic bonds to polymers is one of the most powerful approaches. However, since the reformation of dynamic bonds requires molecular mobility, mechanical strength usually conflicts with an autonomous healing ability. In this review, we overview recent successful approaches to overcome this limitation, as well as attempts to design mechanically robust polymers that can heal with the assistance of ubiquitous stimuli. These approaches include combining careful dynamic bond chemistry choices and smart designs of the environment around the dynamic bonds.

    • Chaehoon Kim
    •  & Naoko Yoshie
  • Original Article |

    An ethylene glycol-based hexa-block copolymer with six different temperature-responsive blocks was prepared via a reversible addition-fragmentation chain transfer (RAFT) polymerization. 2-(2-Methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA) were selected as the ethylene glycol-based monomers. Each block exhibits a different LCST in aqueous solution owing to their different OEGMA contents.

    • Yoko Kudo
    • , Hiromitsu Mori
    •  & Yohei Kotsuchibashi
  • Focus Review |

    A new nucleic acid delivery framework, predicated on a photo-responsive cationic block copolymer (BCP), was used to precisely tune nucleic acid binding and provide spatiotemporal control over gene expression. This innovative platform leveraged a macromolecular design in which the polymer moieties directly responsible for nucleic acid complexation were cleaved from the polymer upon photo-stimulation, significantly enhancing nucleic acid release. Temporal control over polyplex disassembly facilitated development of a potentially universal, kinetic modeling scheme for gene silencing. Furthermore, this versatile BCP-based framework easily accommodated anionic excipients and quantum dot imaging constructs.

    • Thomas H. Epps III
    • , Thu Vi
    •  & Millicent O. Sullivan
  • Original Article |

    We prepared microwave-responsive adhesives from second-generation acrylic adhesives and ionic liquids, and performed microwave-responsive “on-demand-peeling”. The response depended on the types and quantity of the ionic liquids. While the adhesive strength were maintained irrespective of the contents of ionic liquid in the adhesives, with/without microwave irradiation. The peeling of the adhesives was observed in less than 30 s after microwave irradiation. In this study, we proposed simple, conventional, and attractive preparation of microwave-responsive adhesives by adding ionic liquids.

    • Mirei Usuba
    • , Chizuru Hongo
    • , Takuya Matsumoto
    •  & Takashi Nishino
  • Original Article |

    Saturation transfer difference (STD) NMR analysis was performed to identify the titanium-binding peptide (TBP) sites that interact with the SiO2 nanoparticle surface, and then Arg1 and Asp5 were identified to be in close contact with the surface. The structure of the TBP bound to SiO2 determined by the NOESY measurement was well defined, and the Arg1 and Asp5 side chains face in the same direction. These results validates that the NH2+ of Arg1 and the COO of Asp5 interact electrostatically with the SiO and SiOH2+ on the SiO2 surface, respectively.

    • Yu Suzuki
    •  & Heisaburo Shindo
  • Focus Review |

    Soft materials based on colloidal self-assembly in ionic liquids: fundamental studies on the colloidal stability in ionic liquids (ILs) are highlighted. Three different repulsive forces—electrostatic, solvation, and steric—are examined for their effectiveness to stabilize colloidal particles in ILs. An overview of recent studies on colloidal soft materials in the presence of ILs is also provided. Based on suspended states of colloid particles, two different soft materials—colloidal gel and colloidal glass—were prepared in ILs. Their functional properties, including ionic transport, rheological and optical properties, are discussed in relation to the microstructures of the colloidal materials.

    • Kazuhide Ueno
  • Original Article |

    Phosphate-functionalized acrylic materials were synthesized by free-radical polymerizations of MMA and DMP using the BPO-DMpT initiated reaction system. The resulting products were able to react with the HEMA monomer, thus yielding polymers with a chain structure of P(MMA-co-DMP)-b-PHEMA. Remarkably, incorporating DMP and/or PHEMA into PMMA main chain rendered a copolymer with low Tg while increasing the Td intrinsic to PMMA. The enhancement of overall thermal stability of the acrylic materials is a feature of great interest for applications in bone cements and coating system additives.

    • Yun-Fen Peng
    • , Ashley Tsai
    •  & Ming-Hsi Huang
  • Review |

    Recent works revealed that protein and cell resistance of bioinert self-assembled monolayers originates in the physical barrier of the interfacial water. We review the history of the previous works that attempted to clarify the underlying mechanism and discuss prospects to apply the findings to design new biomaterials.

    • Ryongsok Chang
    • , Syifa Asatyas
    • , Ganchimeg Lkhamsuren
    • , Makoto Hirohara
    • , Evan Angelo Quimada Mondarte
    • , Kasinan Suthiwanich
    • , Taito Sekine
    •  & Tomohiro Hayashi