Invited Review

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  • We demonstrate a new methodology of DNA and RNA functionalization with a base surrogate prepared from d-threoninol. With this surrogate, we can introduce functional molecules at any position in the sequence. Our methodology is conceptually similar to copolymerization; phosphoramidite monomers of base surrogates, and natural nucleotides are ‘copolymerized’ on solid supports to prepare functional oligonucleotides. The incorporation of intercalating moieties allows for the design of four stable functional motifs: wedges, interstrand-wedges, dimers and clusters. By selecting suitable functional molecules and motifs, we can design novel photofunctional oligonucleotides.

    • Hiroyuki Asanuma
    • Keiji Murayama
    • Hiromu Kashida
    Invited Review
  • Polymers that contain arylene groups in their main chain are of significant importance because of their applications to semiconducting materials or engineering plastics. Therefore, controlled methods for the synthesis of arylene-containing polymers based on chain-growth polymerization have been intensively developed in polymer chemistry. This review focuses on the advances in chain-growth polymerization accompanied by formation/introduction of arylene groups into polymer main chains.

    • Shingo Ito
    Invited Review
  • Glycosaminoglycans (GAGs) are one of the most important polysaccharide in the living systems. However, preparation of GAGs is difficult owing to the complex structure and high molecular weight. In order to obtain the GAGs’ materials with a practical way, we investigated a new approach to mimic GAGs using polymer chemistry. We reviewed the syntheses of GAGs of the previous reports and the glycopolymers having GAGs moieties, including our GAGs' mimic polymers.

    • Yoshiko Miura
    • Tomohiro Fukuda
    • Yu Hoshino
    Invited Review
  • In this review, we show that using two-dimensional (2D) samples suitable for atomic force microscopy (AFM) observation, especially Langmuir–Blodgett films, molecular images of various polymer structures could be obtained by tapping-mode AFM. The molecular-level observations included isolated polymer chains and their movements on substrates, 2D folded-chain crystals and their melting behavior, crystallization behavior of single isolated chains, supramolecular multistranded stereocomplex and chain packing in monolayers. The molecular-level information obtained by the direct observations should greatly improve our understanding of polymer science.

    • Jiro Kumaki
    Invited Review
  • Susceptible situation of water molecules in the vicinity of lopsidedly charged copolymer films (upper) and a zwitterionic copolymer film. The charge-neutralized polymer surface is less perturbative to the structure of vicinal water. The image first published in Kobunshi 39, 445 (Hot Topics) (2014).

    • Hiromi Kitano
    Invited Review
  • This review focuses on redox-induced molecular actuation in macromolecular and self-assembled systems. Effective amplifications of conformational changes of unit molecular part are explored on the basis of three categories: polymeric system; molecular interactions; and self-assembled system. The importance of highly ordered structures is suggested to effectively amplify conformational change of small molecular unit into macroscopic deformation of bulk materials. Finally, future outlook toward electrochemical soft actuators and tips to prepare stimuli-responsive molecular assemblies, which undergo amplification in conformational change of constituent molecules, are provided.

    • Toshihiro Ohtake
    • Hideki Tanaka
    Invited Review
  • The establishment of a Lewis acid-mediated selective propoxylation reaction using a specific borane catalyst enabled the synthesis of a novel class of PPG with an increased primary hydroxyl content of up to 70%. In addition, we developed a high yielding continuous process for producing the new PPG with a low amount of by-products by using tube reactors combined with film evaporators for by-product removal. Our new PPG achieves an excellent balance between reactivity and humidity resistance. As a result, it has important advantages for a broad area of polyurethane applications.

    • Toru Miyajima
    • Kenji Nishiyama
    • Takayuki Tsuji
    Invited Review
  • For long-lasting implants of an artificial hip joint, it is necessary to reduce the wear of the acetabular liner made with polyethylene (PE). An articular cartilage-mimicking technology has been developed by grafting poly(2-methacryloyloxyethyl phosphorylcholine (MPC)) onto a highly cross-linked PE using photoinduced polymerization. The thickness of the poly(MPC) graft layer is 100–200 nm. The poly(MPC)-grafted PE has been introduced on an artificial hip joint system as a liner for lubrication. This artificial hip joint has been used clinically since 2011 and implanted on over 20 000 patients.

    • Kazuhiko Ishihara
    Invited Review
  • Polypropylene with low isotacticity and high molecular weight is synthesized using specific C2-symmetric doubly bridged metallocene complexes. This polymer possesses some isotactic sequences in random order. Though it is the homopolymer of propylene, it is a characteristic polymer having low melting point, transparency and elasticity. This soft polypropylene does not have the drop in the glass transition temperature, and the drop in the compatibility to polypropylene in comparison with propylene copolymer, which is a kind of the conventional soft polypropylene.

    • Yutaka Minami
    • Tomoaki Takebe
    • Takuji Okamoto
    Invited Review
  • Half-metallocene complexes of the type CpM(L^L)X2 (L^L=chelating ligands) offer the advantage of catalyst modification: by changing one cyclopentadienyl ligand of metallocene complexes to other ligands such as three-, four-, five-, six- and seven-membered chelates, bidentate and tridentate coordination, and monoanionic, dianionic and trianionic system, steric and/or electronic modification of the coordination environment is much flexible. The structural uniqueness of the metal complexes and the effects of the chelate ring sizes on their productivity and activation processes of the metal complexes with cocatalysts are highlighted.

    • Hayato Tsurugi
    • Keishi Yamamoto
    • Kazushi Mashima
    Invited Review
  • Die-bonding film is widely applied for semiconductor package of electronic equipments. The die-bonding film based on epoxy resin/acrylic polymer system shows the higher flexibility to thermal stress during the heat cycle test compared with epoxy–matrix systems. In addition, properties of the film vary widely depending on the ratio of epoxy resin and acrylic polymer contents. To satisfy the target properties, novel material design method named weak conditioned combinatorial linear programming was developed.

    • Teiichi Inada
    Invited Review
  • Self-assembled organic nanotubes (S-ONTs) from rationally designed synthetic amphiphiles provide a variety of inner and outer surfaces as well as homogeneous hollow cylinders with precisely controlled inner diameters. Focusing on distinctive characteristics of the nanospace or nanochannel, we review the recent progress in the research on encapsulation, transportation, stabilization and release behavior of biomacromolecules in the S-ONT nanochannels in terms of application to a bioengineering field.

    • Toshimi Shimizu
    • Hiroyuki Minamikawa
    • Mitsutoshi Masuda
    Invited Review
  • This review introduces recent attempts in the photoalignment processes of liquid crystalline polymers focusing on the two aspects. First, the strategies to ensure effective in-plane alignment of the photoresponsive mesogens are summarized. Despite many investigations reported so far, the film systems have not been optimized for efficient photoreaction. Second, new photoalignable systems involving block copolymer frameworks such as surface-grafted polymers and block copolymer thin films are introduced. The photoalignment processes in such mesoscopic systems involve strong cooperative motions among different hierarchical size features. Based on these approaches, a new strategic platform, photoalignment via a command surface at the free surface, is further proposed.

    • Takahiro Seki
    Invited Review Open Access
  • Polyglycolic acid (PGA) is a novel biodegradable resin. To mass-produce high-molecular-weight PGA on an industrial scale, Kureha Corporation has developed a new process for obtaining high yields of the intermediate glycolide (GL) with high levels of purity. Using the obtained GL, we developed a method to polymerize high-molecular-weight PGA continuously. A commercial production plant is now in operation. We have also developed various new applications that utilize its characteristics. The use of PGA in shale gas and oil exploration is of interest because PGA can supply ultra-strong and biodegradable materials.

    • Kazuyuki Yamane
    • Hiroyuki Sato
    • Yoshiki Shigaki
    Invited Review
  • A number of biomaterials have been proposed, including hydrophilic, phase-separated and zwitterionic polymers. It has not been clearly elucidated which mechanisms are responsible for biocompatibility on a molecular level. Water interactions have been recognized as a fundamental part of the biological response to contact with biomaterials. We have proposed the ‘intermediate water’ concept; the water exhibited both clear peak for cold crystallization in differential scanning calorimetry chart and a strong peak at 3400 cm−1 in a time-resolved infrared spectrum. We found the localized hydration structure consisting of the three hydrated water in poly(2-methoxyethyl acrylate) (PMEA).

    • Masaru Tanaka
    • Tomohiro Hayashi
    • Shigeaki Morita
    Invited Review
  • This review describes the developments of self-assembled photonic crystals (PCs) of chiral liquid crystals (CLCs) and colloidal crystals (CCs) for laser applications. Both CLCs and CCs have intrinsic capabilities to spontaneously assemble 1D-PCs and 3D-PCs, respectively. By combining fluorescence dyes in the structures, the stimulated laser action can be generated by optical excitation. Moreover, the optically excited lasing is controllable by external stimuli due to their self-organization. This review highlights the research backgrounds of CLCs and CCs, as well as the experimental results of soft and tunable laser applications.

    • Seiichi Furumi
    Invited Review
  • This article reviews recent findings on the optical, electro-optic, and optoelectronic properties of natural and chemically modified DNAs. This review specifically deals with photoluminescence and ET, lasing, NLO, organic light-emitting diode, and photovoltaic characteristics of various compositions based on natural and modified DNAs. Replacement of the Na+ counter-ions of natural DNA with functionalized cationic moieties is rapidly broadening the possible utilizations of DNA-based novel materials.

    • Young-Wan Kwon
    • Dong Hoon Choi
    • Jung-Il Jin
    Invited Review
  • Poly (butylene succinate)(PBS) nanocomposites and PBS ionomer were prepared by in situ polymerization. This review focused on the effect of the modified clay, TS-1 zeolite and ionic group in PBS matrix on physical properties, rheological properties, crystallization behavior and biodegradability control.

    • Sung Yeon Hwang
    • Eui Sang Yoo
    • Seung Soon Im
    Invited Review
  • Supramolecular polymer is broadly defined as any type of an assembly formed from one or more molecular components via reversible bonds; therefore, monomeric and polymeric states are in equilibrium over the relevant experimental timescale. Structural and dynamic properties of supramolecular polymers, including the degree of polymerization (DP), chain lifetime and conformational flexibility, are influenced by external stimuli; thus, these result in supramolecular ‘smart’ materials, which offer adaptivity that leads to easy fabrication, stimuli responsiveness and self-healing at the forefront of science and engineering. This review will focus on the recent developments in supramolecular polymers composed of discrete repeating units, as well as novel supramolecular materials produced by the interplay of supramolecular and polymer chemistry.

    • Takeharu Haino
    Invited Review
  • We have proposed the concept and significance of nano-alloyed polymer, which includes nano-dispersed domains, and have developed the biaxially stretched film with higher glass transition temperature and improved dimensional stability as compared with regular poly(ethylene terephthalate) film (Figures 1 and 2). Highly concentrated polyimide master batches are made at much lower temperature compared with regular processing temperature. The nano-alloyed film is obtained by film-making process having biaxial stretching and heat treatment. The nano-sized domains have an important role as pseudo-cross-linkage points, for demonstrating good drawing process ability and high orientation.

    • Tetsuya Tsunekawa
    • Takuji Higashioji
    • Ichiro Ishizuka
    Invited Review