Polymers - Vol. 58, No. 6 (June, 2009)

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Vol. 58, No. 6 June,( 2009)

Controlled and Self-Assembled Nanostructured Thin Films beyond Microscopic and Materials Fields
Tomokazu IYODA
Division of Integrated Molecular Engineering, Chemical Resources Laboratory, Tokyo Institute of Technology

The finer structures are resolved in a microscope's field of view, the broader outlook is lost. One image often says too much since nobody, except an observer, knows the overview image. Such inevitable problem has been encountered on microscopic observation of nanostructured materials in recently developed nanoscience and nanotechnology. Newly developed amphiphilic liquid crystalline block copolymers form normally oriented PEO cylindrical nanodomains in their thin films, successfully fabricated in a meter-sized area, e.g., on a roll-type PET film substrate by continuous coating with a microgravure. This success allows one to use them as reliable nanotemplates for structural transcription to and hybridization with various materials such as metal, semiconductors, and so on. We hope that such reliable nanotemplates will stimulate various fields to explore new nanohybrid materials with interactive functions. Polymer Preprints, Japan 2009, 58, 25.

π-Stacked Polymers: Synthesis, Structure, and Function
Tamaki NAKANO
Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University
Conformational regulation of polymer chains is an important goal in polymer synthesis because chain conformation often remarkably affects properties of polymeric materials. We have synthesized polymers having a novel "ƒÎ-stacked conformation" by vinyl polymerization of dibenzofulvene (DBF) and its derivatives. In the ƒÎ-stacked conformation of poly(DBF) and its derivatives, side-chain fluorene chromophores were regularly stacked on top of each other and main-chain C-C bonds revealed a slightly twisted all-trans structure. The ƒÎ-stacked conformation was identified by single-crystal X-ray analyses and 1H NMR spectra of uniform oligo(DBF)s prepared with anionic initiators and isolated by size-exclusion chromatography. Poly(DBF) exhibited energy and charge delocalization over the stacked ƒÎ-electron systems, suggesting that ƒÎ-stacked polymers will be useful as molecular wires conveying energy and charges. Furthermore, conformational chirality was successfully introduced to ƒÎ-stacked polymers. Polymer Preprints, Japan 2009, 58, 37.

Development and Applications of Polyolefin and Rubber Clay Nanocomposites
Arimitsu USUKI*, Makoto KATO, Naoki HASEGAWA, Hirotaka OKAMOTO, and Masaya KAWASUMI
TOYOTA Central Research and Development Labs., Inc.
A nylon6 clay hybrid (nanocomposite, NCH) was developed by TOYOTA CRDL group. In the NCH, the silicate layers of clay mineral are dispersed on a nano-meter level and are strongly interacted with the matrix, which leads to significant improvements in the mechanical properties of the material and the discovery of unexpected new properties. Polyolefins (PP, PE etc) are the most widely used polymers, and therefore the discovery of a polyolefin clay nanocomposite has been desired for a long time. Since a polyolefin does not include any polar groups in its backbone, it was thought that the homogeneous dispersion of the silicate layers can not be realized. However, we have developed successfully a polypropylene(PP) clay nanocomposite using organo-clay and modified PP as shown in Fig. 1. Polymer Preprints, Japan 2009, 58, 31

Development of a Biaxially Stretched Nano-Alloyed Film
Tetsuya TSUNEKAWA*, Takuji HIGASHIOJI, Hirofumi HOSOKAWA, Akira KUBOTA, and Ichiro ISHIZUKA
Toray Industries, Inc.
We have proposed the concept and significance of a nano-alloyed polymer, which includes nano-dispersed domains, and have developed a bi-axially stretched film with higher glass transition temperature and improved dimensional stability as compared to a regular PET film (Fig.1 and 2). Nanosized polyimide domains are dispersed using by our original melting extrusion process. In this process, a high concentrated polyimide masterbatch is made at much lower temperature compared to the regular processing temperature of the polyimide. The nano-alloyed film is obtained by a film making process using a bi-axially stretching and heat treatment. The nanosized domains play an important role as pseudo cross-linking points, for demonstrating uniform drawing and high orientation through stretching process. Polymer Preprints, Japan 2009, 58, 28.

Development of a New Separator as an Important Innovation of the Lithium Ion Battery (LIB)
Haruyuki YONEDA* and Yoshifumi NISIMURA**
Asahi Kasei Co.* Asahi Kasei Chemicals Co.**
Today the Lithium-Ion Battery is a necessity as energy storage device for cellular phones, notebook PCs, etc. The key to even further dissemination of the LIB was to add a safety function to prevent thermal abuse, and therefore the separator was required to have a safety function. As the first group we have developed a polyethylene micro-porous membrane with a safety function. Our key to success was the introduction of a new concept into the thermal induced phase separation method. The developed safety function includes features like melting polyethylene, closing membrane micro-pores and shutting-down lithium ion transportation at overcharge abuse. Furthermore, we succeeded in giving the developing process full control over the pore size in a range from small diameter, 0.1 ƒÊm up to large, 0.5 ƒÊm. Asahi KASEI has more than 50% share of the global LIB separator market. The half of today's world population uses cellular phones and the half of them employ our separator. Polymer Preprints, Japan 2009, 58, 34.

Single PMMA Chain in Ultra-Thin Film Imaged by Near-Field Optical Microscopy
Hiroyuki AOKI
Department of Polymer Chemistry, Kyoto University
The conformation of a poly(methyl methacrylate) (PMMA) chain in an ultra-thin film is discussed by the direct observation of the individual chains using scanning near-field optical microscopy (SNOM), which allows the optical imaging with high spatial resolution beyond the diffraction limit of light. The conformation of the individual PMMA chain in a thin film was directly observed by SNOM, and we examined the effect of the spatial constraint in the thin film on the chain dimension in the film plane, Rxy. In the thickness range of 1 ~ 100 nm, Rxy in an ultra-thin film was not significantly altered from that in the bulk state, indicating the lowered interchain entanglement in the ultra-thin film. Polymer Preprints, Japan 2009, 58, 81. H. Aoki, et al., Polymer Journal 2008, 40, 274.

Intrinsic Viscosity of Wormlike Regular Three-Arm Stars
Daichi IDA
Department of Polymer Chemistry, Kyoto University
The ratio gā of the intrinsic viscosity of the Kratky-Porod (KP) wormlike regular three-arm star touched-bead model (Fig. 1) to that of the KP linear one, both having the same (reduced) total contour length L and (reduced) bead diameter db, is evaluated in the Kirkwood-Riseman approximation, and its behavior as a function of L and db is examined (Fig. 2, unfilled circles). It is found that gā remarkably depends not only on chain stiffness (L) but also on chain thickness (db). An empirical interpolation formula for gā (Fig. 2, solid curves) is also proposed, which is considered to be useful for practical purposes. Polymer Journal 2008, 40, 257.

Enhanced Photocurrent Generation by Electron Hopping through Regularly- Arranged Chromophores in a Helical Peptide Monolayer
Tomoyuki MORITA
Graduate School of Engineering, Kyoto University
Novel 310-helical peptides carrying naphthyl groups at the side chains in a linear manner were self-assembled on gold to form a well-ordered self- assembled monolayer with vertical orientation. Upon photoexcitation of the naphthyl groups with an electron donor, the longest peptide generated the largest anodic photocurrent. Theoretical simulations successfully demonstrated that the helix scaffold with many naphthyl groups in a linear manner was effective to suppress quenching by gold due to the elongation of the helix length, and to promote electron hopping among the naphthyl groups enabling long-range electron transfer from the distant naphthyl group to gold, eventually realizing a molecular system efficiently generating a photocurrent. Polymer Journal 2008, 40, 700.

Polymer-DNA Block Type "Smart" Conjugate for DNA Analysis
Naoki KANAYAMA* , Tohru TAKARADA, and Mizuo MAEDA
Bioengineering Laboratory, RIKEN Advanced Science Institute  Present Address. Department of Material Science, Graduate School of Pure and Applied Science, University of Tsukuba (kanayama@ims.tsukuba.ac.jp)
The field of controlled radical polymerization has undergone rapid development in the past decade, and its application has been demonstrated in a wide variety of fields. However, there are only a few examples that utilize the character of well-controlled polymers to bioanalytical purposes. Our group has recently developed a facile and useful method of synthesizing a well-controlled block type conjugate between a RAFT-generated polyacrylamide and an oligodeoxyribonucleotide. We demonstrated that the obtained conjugate polymer served as an affinity polymeric probe in a single-nucleotide polymorphisms (SNP) genotyping based on a free-solution capillary electrophoresis. In our system, the conjugate polymer was utilized as "drag", which regulates the electrophoretic mobility of target DNA in a sequence specific manner. Consequently, we succeeded in discriminating single-base difference within a 60 mer DNA sequence. Polymer Preprints, Japan 2008, 57, 1832.

Reversible Phototriggered Micromanufacturing Using Amorphous Photoresponsive Molecular Film
Takashi UBUKATA
Department of Advanced Materials Chemistry, Graduate School of Engineering, Yokohama National University
Azobenzene-containing films are interesting materials because they self-organize surface relief structures on the micrometer and nanometer scales in response to spatio-patterned light. We have found a methodology to develop the latter mentioned phenomenon into various thin photoresponsive molecular films from a compound other than azobenzene derivatives. Surface relief structures are formed on amorphous films composed only of highly durable spirooxazine molecules by spatio-patterned ultra-violet light due to the mass transfer. The structure can be erased by heating and can be reformed by illumination with spatio-patterned light again. This is the first reversible surface relief formation using a photoresponsive molecule other than the azobenzene-related compounds. Kobunshi Ronbunshu 2008, 65, 536.

Colloidal Complexes Obtained from Charged Block Copolymers and Surfactants
Masahiko ANNAKA
Graduate School of Science, Kyushu University
Complexes involving oppositely charged polyelectrolyte or polyelectrolyte and surfactant constitute an active field of research. These systems show similarities in structure and behavior with more complex biological macromolecular self-assembled systems, such as lipoproteins and protein/DNA complexes. We investigated the structure and the stability of a colloidal complex made from neutral-anionic block copolymer and cationic surfactant. For a surfactant-to-polymer charge ratio lower than the critical value ZC, the colloidal complexes are single surfactant micelles dressed by a few block copolymers. Above ZC, the colloidal complexes form a core-shell structure, of which the core is a dense and disordered microphase made of surfactant micelles connected by the polyelectrolyte blocks. The corona was a diffuse shell of the neutral chains and it ensured steric stability. Langmuir 2008, 24, 5707.

Chemoenzymatic Synthesis of Amylose-Grafted Polysaccharides
Yoshiro KANEKO and Jun-ichi KADOKAWA*
Graduate School of Science and Engineering, Kagoshima University
Novel branched heteropolysaccharides such as amylose-grafted chitosan and cellulose were prepared by a chemoenzymatic method according to a following example of procedures. A maltoheptaose was chemically introduced into chitosan or amine-functionalized cellulose by reductive amination to produce the maltoheptaose-grafted chitosan and cellulose, respectively. Then, the phosphorylase-catalyzed enzymatic polymerization of glucose 1-phosphate from the maltoheptaose graft-chain on the chitosan and cellulose derivatives was performed to produce corresponding amylose-grafted polysaccharides, respectively. The obtained materials showed different properties from original polysaccharides. For example, hydrogels and films were easily formed from the materials. These properties were probably caused by formation of aggregates as a result of the crystalline structure of amylose graft-chains. Polymer Preprints, Japan 2008, 57, 4868.