Kobunshi - Vol. 59, No. 6 (JUne, 2010)

Hot Topics

Vol. 59, No. 6, June (2010)

Novel Colorless Polyimides and Their Applications
Masatoshi HASEGAWA
Faculty of Science, Toho University

Polycondensation of diamines with three isomers of hydrogenated pyromellitic dianhydride, i.e., H-PMDA, H'-PMDA, and H"-PMDA leads to colorless polyimides (PIs) with quite different peculiar properties. 1R, 2S, 4S, 5R- cyclohexane tetracarboxylic dianhydride (H"-PMDA) drastically improves the solubility of PIs on the basis of its highly bent steric structure (Fig.1) while keeping very high glass transition temperatures. H"-PMDA-based PI systems can be applied to plastic substrates in flat panel displays, optical waveguiding materials, and optical compensation films in LCDs. The copolyimide films derived from H"-PMDA with 2,2'- bis(trifluoromethyl)benzidine and fluorene-containing diamines can be directly formed on TAC films by casting of its cyclopentanone solution. The colorless PI films obtained display both of relatively high birefringence (Dn=nin - nout > 0.02) and very low wavelength-dispersity of birefringence (or retardation), namely, Dn450/Dn550 =1.01. Thus, the present PI systems can be used as a new type of optical compensation film materials. PMF Preprints, Japan 2009, 18, 152.

Directed Self-Assembly of POSS-Containing Block Copolymers
Teruaki HAYAKAWA
Department of Organic and Polymeric Materials,
Tokyo Institute of Technology
The use of block copolymer (BCP) materials in thin-film formation to create dense, periodic arrays of small features termed as Òblock copolymer lithography" has inspired the synthesis of a rich array of new BCPs. Organic-inorganic hybrid BCPs are of interest to enhance the repulsion in the microphase-separation and the etch selectivity to oxygen plasma between the blocks compared with conventional organic-organic BCPs for nanopatterning templates. We have focused on one such example of an inorganic precursor of polyhedral oligomeric silsesquioxane (POSS)-containing BCPs. The living anionic polymerization route to POSS-containing BCPs afforded not only the narrow polydispersity index and high degree of polymerization, but also the formation of vertically oriented lamellae and cylinders in the thin films. The excellent self-assembling characteristics and etch selectivity make these POSS-containing BCPs an ideal candidate for BCP lithography. PMF Preprints, Japan 2009, 18, 166

Rechargeable Direct Carbon Fuel Cell: High Temperature Portable Fuel Cell Using Solid Carbon Fuel
Manabu IHARA
Department of Chemistry
(Inter-Departmental Organization for Environmental and Energy),
Tokyo Institute of Technology
This fuel cell, called a Rechargeable Direct Carbon Fuel Cell (RDCFC), uses solid oxide electrolyte and operates at high temperature. The RDCFC generates electric-power using carbon fuel that is charged by the decomposition of a hydrocarbon. The RDCFC utilizes unique reactions, namely, electrochemical oxidation of not only carbon but also CO produced by the reaction of CO2 with C. Because no gas is supplied to RDCFC during power generation, the anode of RDCFC is almost a closed system. The power generation characteristics are stable because the partial pressure of CO and CO2, which are produced by electrochemical reactions, can be kept constant at thermal equilibrium composition while carbon fuel is present. In principle, 100% fuel utilization can be achieved, and the theoretical efficiency (DG/DH, determined by thermodynamics) is about 100%. Because the energy density of solid carbon is higher than that of either gas or liquid fuel, the RDCFC is expected to be a compact, high efficiency electric power generator. Expected applications include portable power sources for PCs, power sources for electric vehicles, on-site power generators in buildings, and power generators in large-scale power plants. PMF Preprints, Japan 2009, 18, 162.
文献 M. Ihara and S. Hasegawa, J. Electrochem. Soc., 153, A1544(2006)
S. Hasegawa and M. Ihara, J. Electrochem. Soc., 155, B58(2008)

Development of Polyion Complex Vesicles ÔNano-PICsomes' with Tunable Size and Stability in Submicron Region
Akihiro KISHIMURA, Yasutaka ANRAKU, and Kazunori KATAOKA
Graduate School of Engineering, The Universtiy of Tokyo
Self-assembling fabrication of monodispersed vesicles has recently received much attention from both fundamental and applied standpoints in the biomedical field. In this study, we report the first example of spontaneously formed unilamellar polyion complex vesicles (Nano-PICsomes) through self-assembly of pairs of oppositely charged PEG-block-aniomers and homo-catiomers in aqueous medium. Vesicle sizes are tunable in the range of 100-400 nm with a narrow size distribution, simply by changing the total polymer concentration. Also, Nano-PICsomes were able to encapsulate water-soluble fluorescent macromolecules in the inner water phase and release them slowly into exterior. Moreover, cross-linking of the vesicle membrane allows tuning of permeability, enhancement in stability under the physiological condition, and preservation of size and structure even after freeze-drying and centrifugation treatment. Finally, we demonstrated an excellent blood-circulation property of Nano-PICsomes in the bloodstream of mice. PMF Preprints, Japan 2009, 18, 208. J. Am. Chem. Soc. 2010, 132, 1631.

Fast Dynamics and Conformations of Polymer in a Conformational Disordered Crystal Characterized by 1H-13C WISE NMR
Toshikazu MIYOSHI
National Institute of Advanced Industrial Science and Technology,
Research Institute of Nanotechnology
1H-1H residual dipolar interactions are utilized for determination of multi-site dynamics of form II of isotactic-poly(1-butene) (iPB). Complex backbone and side-chain dynamics at the fast motional limit effectively suppress multi-spin interactions and result in apparent 1H spinning-side band patterns under even a slow MAS frequency at 373 K. The observed dipolar patterns obtained by 1H-13C WISE NMR and their analyses under a two spin approximation indicates that the stems perform continuous diffusions around their axes and the side groups independently show conformational transitions between two conformations with dihedral angles of 88 and 268 ± 10ﾟ at 373 K. PMF Preprints, Japan 2009, 18, 19.

Nonaqueous Polymer Dispersion Using Fluoropolymer
as Dispersant : F-NAD
Nobushige NUMA
KANSAI PAINT Co., Ltd.
Fine dispersions of acrylic polymer stabilized with fluoropolymer in organic solvent (F-NAD) were prepared by means of precisely controlled dispersion polymerization. The dispersant is the copolymer of fluoroethylene/vinyl ethers (or vinyl esters) which has some hydroxy functionalities and is soluble in various organic solvents. Many types of surface coatings formulated with F-NAD have been manufactured without any problems since 1985 and proved to retain the excellent weather and chemical resistance comparable to the fluoropolymer for outdoor use. PMF Preprints, Japan 2009,18, 27.

Radical Batteries with Ultimate Population of Unpaired Electrons
Kenichi OYAIZU
Department of Applied Chemistry, Waseda University
The growing interest in organic electroactive elements for charge transport, separation and storage processes have led to the displacement of inorganic materials in electronic devices. We have been focusing on the strategies based on the integration of unpaired electrons. We have synthesized a series of organic radical polymers bearing unpaired electrons of robust radical groups as pendants per repeating unit. A large population of the unpaired electron allows the efficient redox gradient-driven electron transport via charge hopping between the isolated but densely populated redox sites by self-exchange reactions. The radical polymers are emerging as a new class of electroactive materials for batteries which are characterized by excellent rate performances. PMF Preprints Japan 2009, 18, 164 Adv. Mater. 2009, 21, 2339.

Low Temperature Printing Technique for Metal Electrode on Plastic Film
Manabu YOSHIDA
National Institute of Advanced Industrial Science and Technology
We have newly developed a mechanical sintering technique in which a mechanical force is applied to a printed metal pattern. Using this technique, we have succeeded in the preparation of an aluminum, zinc, copper and tin electrode on a plastic substrate. We have also succeeded in preparing a metal alloy ink to control the work function of a printed electrode. The work function of the electrode was controlled by changing the composition of these metal contents in an alloy ink. By applying our developed mechanical sintering technique on the printed alloy pattern, a printed electrode with various work functions from 3.5 eV to 5 eV could be prepared on a plastic substrate. These printed alloys were effective to improve the performance of printed diode and transistors. PMF Preprints, Japan 2009, 18, 150.

Development of Ionene Polymers as Novel Polymeric Gelators
Masaru YOSHIDA
Nanosystem Research Institute,
National Institute of Advanced Industrial Science and Technology
Recently, we reported a novel ionic gelator based on the cationic ionene oligomer with pyridinium moieties in the main chain. The gelator was easily prepared by a one-pot condensation reaction of commercially available 4-aminopyridine and (4-chloromethyl) benzoyl chloride under basic condition. The following remarkable characteristics were also observed for the gelator: (a) Acid resistance; (b) Application to a broad range of solvent i.e. organic solvents and Òionic liquids" by facile anion-exchange; (c) Efficient dispersant for single-walled carbon nanotube (SWNT); (d) Self-healing property after the mechanical collapse. As a part of our research on the ionic gelator, we also synthesized new ionene polymers with tetraalkylammonium parts as the main chain by the copolymerization of 1,4-bis[4-(chloromethyl)benzamido]benzene and N,N,N',N'-tetramethylalkylene diamines, showing a similar gelation property. PMF Preprints Japan 2009, 18, 182