Kobunshi - Vol. 58, No. 12 (December, 2009)

Hot Topics

Vol. 58, No. 12, December ( 2009)

Development of Polymer Gels with Autonomous Responding Function
Ryo YOSHIDA
Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo

To obtain a novel biomimetic polymer, we have been studying polymers with an autonomous self-oscillating function. We succeeded in developing a novel self-oscillating polymer and gel by utilizing the oscillating reaction, called the Belousov-Zhabotinsky (BZ) reaction, which is recognized as a chemical model for understanding several autonomous phenomena in biological systems. The self-oscillating polymer is composed of a poly(N-isopropylacrylamide) network in which the catalyst for the BZ reaction is covalently immobilized. Under the coexistence of the reactants, the polymer undergoes spontaneous cyclic soluble-insoluble changes or swelling-deswelling changes (in the case of gel) without any on-off switching of external stimuli. Several kinds of functional material systems utilizing the self-oscillating polymer and gel such as biomimetic actuators, mass transport surface, etc. are expected.Polymer Preprints, Japan 2009, 58, 2192.

Studies on Preparation and Application of Hyperbranched Polymers
Masa-aki KAKIMOTO
Tokyo Institute of Technology
Various kinds of hyperbranched polymers have been synthesized. Some of them were applied as new useful materials. (1)Hyperbranched siloxysilanes were synthesized. This material had an unusual adhesion ability on inorganic surfaces, and was applied as ÒPolymer BrushesÓ. (2)New preparation method, A2 + B3 method, was developed in polyamides and polyimides systems. Hyperbranched phthalocyanine was synthesized using this methodology, and was applied as a hole injection layer of OLED and inorganic-organic composites having high dielectric constant which is useful for capacitors in embedded circuit boards. (3)Hyperbranched poly(ether sulfone) that possessed sufonic acid groups at the terminus was applied as a ion exchange membrane. In this case, hyperbranched and linear polymers hybrids were prepared to improve the weak mechanical property of hyperbranched polymers.Polymer Preprints, Japan 2009, 58, 2195.

Rewritable Bragg Holograms by Means of Liquid-Crystalline Polymers
Atsushi SHISHIDO
Chemical Resources Laboratory, Tokyo Institute of Technology
Copolymers were synthesized with azobenzene methacrylate, cyanobiphenyl methacrylate, and alkyl methacrylate, in which the azobenzene acts as a photoresponsive part to undergo photoisomerization, the cyanobiphenyl is involved in a change in refractive index triggered by the photoisomerization of the azobenzene, and the alkyl methacrylate is used to prevent light scattering, respectively. When two writing beams were interfering in the thick polymer films, the diffraction of a probe beam was observed. The first-order diffraction efficiency reached 100%. It is clear that the intensity of the zeroth-order beam is transferred to that of the first-order diffraction with no optical loss due to the formation of the Bragg gratings. When the writing beams were turned off, the diffraction efficiency remained unchanged. However, the grating was easily erased when heated up above Tg for several seconds, and rewritability was confirmed.Polymer Preprints, Japan 2009, 58, 2198.

Rational Design of Functional DNA with Threoninol-nucleotides
Hiroyuki ASANUMA
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University
The growing field of DNA technology requires new modified DNAs that can perform advanced functions. Accordingly, a facile and effective method of rationally designing new functional DNA is highly desired for further ÒevolutionÓ of DNA. Acyclic d-threoninol tethering functional molecule, Òthreoninol-nucleotideÓ, was found to be compatible with natural DNA. Wedge-type (bulge-type) insertion of multiple threoninol-nucleotides tethering intercalators to DNA does not destabilize the duplex, although the backbone structure is greatly changed. Rather, intercalation offsets such distortions and fairly raises the melting temperature of the DNA duplex. With threoninol-nucleotides, photoresponsive DNA and new molecular beacons that can detect single nucleotide polymorphisms (SNPs) and insertion/deletion (indel) polymorphisms have been designed. Furthermore, a variety of molecular clusters have also been prepared from threoninol-nucleotides.Polymer Preprints, Japan 2009, 58, 2207.

Feedstock Recycling of Waste Plastics Using Sub- and Supercritical Fluids
Motonobu GOTO
Bioelectrics Research Center, Kumamoto University
Near their critical point, fluids such as water or alcohols have superior properties as reaction media, which can be used for chemical recycling of waste plastics. Decomposition reactions proceed rapidly and selectively in sub- and supercritical fluids compared to conventional processes. Condensation polymerization plastics such as PET, nylon, polyurethane, and polycarbonate, are relatively easily depolymerized to their monomers in supercritical water or alcohols without catalyst. The reaction mechanism and kinetics had been studied and a commercialization oriented study was carried out with a pilot-scale plant. Addition polymerization plastics can also be decomposed. Fiber and chemicals can be recovered from fiber reinforced plastics containing glass or carbon fiber. Industries have been developing the processes in pilot scale to commercialize the technology.Polymer Preprints, Japan 2009, 58, 2204.

Unique Texture of a Physical Gel
Isamu KANEDA
The department of Food Science, Rakuno Gakuen University
We developed a new type of hydrophobically modified ethoxylated urethanes (HEURs) which has C24 alkanes at the both ends of the polymer as a cosmetic viscosity thickener. As well known, HEURs aqueous solution exhibits a Maxwell type mechanical spectrum. C24HEUR also showed such typical mechanical property. Of special interest in this polymer is the fact that the mechanical relaxation time of its solution was almost equal to the human motion, namely rubbing or mastication. The investigation of the transient behavior during deformation is one of the most important issues for considering the texture of foods or cosmetics. The viscosity growth behavior under the step shear flow was studied for the purpose. Unusual stress upturn behavior was observed under a certain condition as shown in the fig. Such a unique mechanical property may relate to its unique texture in a cosmetic formulation.Polymer Preprints, Japan 2009, 58, 2210.

Synthesis and Properties of Substituted Polyacetylenes - Recent Advances
Toshio MASUDA
Department of Environmental and Biological Chemistry, Faculty of Engineering, Fukui University of Technology
We have been studying the synthesis and properties of substituted polyacetylenes. The work has been reviewed in the reference below. Among them, we developed new Rh-based catalysts; one of them is a cationic Rh complex bearing a fluorine-containing ligand which shows high catalytic activity, and another is a chiral catalyst which induces asymmetric polymerization of phenylacetylene derivatives. As another topic, we have developed highly gas-permeable substituted polyacetylenes. We synthesized poly(1-trimethylsilyl-1-propyne) for the first time in 1983, and found this time that the fluorine- and polymethylated indan-containing polyacetylene shows even higher gas permeability. Thus, after 25 years we could find a polymer that is more gas-permeable than poly(TMSP).Polymer Preprints, Japan 2009, 58, 2734.

Design of Functionalized DNA Molecules Toward Nanobiotechnology
Naoki SUGIMOTO
Faculty of Frontiers of Innovative Research in Science and Technology (FIRST) and Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University
DNA has many remarkable properties that cannot be attained with other molecules. The ability of DNA to form the base pairing and the structural polymorphism allow the formation of distinct secondary and tertiary structures, and may have a catalytic or an aptamer function. We investigate the thermodynamic parameters of DNA structures under various conditions. The data regarding the DNA interaction energy can be applied for molecular design that is used in non-aqueous media, such as intracellular conditions and the surface of the DNA chip or the biosensor materials. We have found the quantitative data of the DNA interaction energy to be very valuable for the rational design of artificial DNAs including the base pair-mimic nucleosides, for DNA molecules being used in logic gate operation and for the design of DNA material containing a bipyridine unit, which is useful as the a nanobiodevice and nanobiomaterial.Polymer Preprints, Japan 2009, 58, 5273. Bull. Chem. Soc. Jpn. (Award Account), 2009, 82, 1.

Nanoporous Polymeric Materials by Phase Separation
Hiroshi UYAMA
Graduate School of Engineering, Osaka University
Porous polymer monoliths are a new category of materials developed during the last decade. The monolithic polymeric materials with well-defined pore properties and surfaces are suitable as chromatographic separation media, ion exchange resins, and catalyst supports. Recently, we have fabricated an acrylic resin (poly(methyl methacrylate), PMMA) monolith by thermally-induced phase separation of the polymer in an aqueous ethanol via convenient processes. The monolith filters for bio-related and environmental applications were developed by the phase separation of the epoxy-containing polymethacrylate, followed by the introduction of the functional groups into the monolith. Poly(lactic acid) monolith was obtained by the phase separation in a mixture of 1,4-dioxane, acetone, and water. Furthermore, the phase separation was applied for the surface modification to create the micro patterned structure by solvent soaking. Polymer Preprints, Japan 2009, 58, 2180.