Kobunshi - Vol. 58, No. 11 (November, 2009)

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Vol. 58, No. 11, November ( 2009)

Novel Shape Memory Polymer using Delay and Thermal Hysteresis of Crystalline Phase Transition in Cross-Linked Polybutylene Succinate
Kazuhiko INOUE* and Midori YAMASHIRO
Nano Electronics Research Laboratories, NEC Corporation

Polybutylene succinate cross-linked with polyisocyanate was found to be an attractive shape memory polymer because it is easily deformed at room temperature and the deformed shape is heat resistant. We discovered that these practical characters are results of thermal hysteresis of the crystalline phase-transition temperature. This hysteresis is caused by hydrogen bonding between urethane functions and covalent bonding in the cross-linked structure, since these connections restrain the PBS molecule and disturb the phase transition from the amorphous to the crystal phase. This shape memory polymer can be easily fitted to a human body without burning it and might therefore soon be used in wearable products. Polymer Journal 2009, 41, 586.


Energy Transfer by Encapsulation of Organic Dyes into p-Conjugated Molecules Containing o-Carborane with Aggregation-Induced Emission (AIE) Property
Kenta KOKADO, Atsushi NAGAI, and Yoshiki CHUJO*
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University
Introduction of o-carborane into p-conjugated molecules resulted in the occurrence of aggregation-induced emission (AIE); i.e., nonemissive molecules are induced to emit intensely by aggregate formation. Stern-Volmer (SV) quenching of the aggregates (Ksv=7.7~103 M-1) by nitrobenzene indicates the encapsulation of small organic molecules into the aggregation. Encapsulation of other fluorophores in the aggregates protected the fluorophore molecules from the formation of H-type aggregation even in water, and the energy transfer phenomenon from the AIE molecule to the fluorophore led to emission from fluorophores. Moreover, it was found the form of the encapsulating aggregation differs from the aggregates consisting of only AIE molecules, probably due to the crystal growth configuration of encapsulated fluorophore molecules. Polymer Preprints, Japan 2009, 58, 182. Macromolecules 2009, 42, 1418.

Interaction of Alzheimer Amyloid b with Glycosaminoglycan Model Polymer
Yoshiko MIURA* and Hikaru MIZUNO
Japan Advanced Insitute of Science and Technology
We synthesized a novel glycopolymer library with 6-sulfo-GlcNAc and glucuronic (GlcA) acid based on the glycosaminoglycans. The molecular weights of the polymers were controlled via living radical polymerization. The interactions between Ab(1-40) and glycopolymers were analyzed by ThT fluorescence assay, atomic force microscopy observation and CD spectra. The glycopolymers carrying 6-sulfo-GlcNAc showed inhibition activity toward Ab aggregation, and the terpolymer with 6-sulfo-GlcNAc and GlcA showed the largest inhibition activity. The glycopolymers with smaller molecular weights showed stronger inhibition activity. The glycopolymers with GlcA induced partial helical conformation in Ab. The glycopolymer libraries yielded valuable information about Ab aggregation with glycosaminoglycans. Polymer Preprints, Japan 2009, 58, 17501.

Remarkable Atherogenic Index by Quaternized Nanogel Sequestrant: New Cholesterol Scavenger Based on Nanotechnology
Yukio NAGASAKI
Tsukuba Research Center for Interdisciplinary Materials Science, University of Tsukuba
It is well known that hyperlipidemia is a risk factor for versatile diseases such as arteriosclerosis, myocardial infarction and cerebral apoplexy. Recently, we have designed PEGylated nanogel bearing quaternary amino groups in the gel core. The size of the nanogel was ca. 100 nm possessing poly(ethylene glycol) tethered chains as a shell in order to improve biocompatibility. Since the nanogel possesses quaternary amine, we tried it as a bile acid adsorbent. The efficiency of reducing LDL level was almost the same as compared to the commercial adsorbent, cholebine. It is interesting to note, on the contrary, that this quaternary amine nanogel increased high density lipoprotein (HDL)-cholesterol level in serum by oral administration, and consequently, extremely high atherogenic index (HDL- cholesterol / LDL-cholesterol) was attained. Though we have not elucidated the mechanism yet, we believe that it is promising as new sequestrant to control balance of LDL and HDL cholesterol level. Polymer Preprint, Japan 2009, 58, 1916.

Fluorescent Nanogel Thermometer for Intracellular Thermometry
Kohki OKABE
Graduate School of Pharmaceutical Sciences, University of Tokyo
The temperature of a living cell is changeable during every cellular event such as cell division, gene expression, enzyme reaction, and metabolism. Thus, measuring intracellular temperature will contribute to the explanation of intricate biological processes and the development of a new diagnosis. Here we demonstrate the first intracellular thermometry with a synthetic fluorescent nanogel thermometer. This nanogel, consisting of a thermosensitive cross-linked polymer and water sensitive fluorescent dye, is superior to other candidate thermometers in biocompatibility (i.e., size, sensitivity, and solubility) and functional independence (i.e., negligible interactions with cellular components). Intracellular temperature variation associated with biological processes can now be monitored by this fluorescent nanogel thermometer with a high temperature resolution of better than 0.5ûC. Polymer Preprints, Japan 2009, 58, 1724.

A Stereoregular Phenolic Resin with High Refractive Index and Low Birefringence
Yusuke TOJO* and Gen-ichi KONISHI
Department of Organic and Polymeric Materials, Graduate School of Science and Engineering, Tokyo Institute of Technology
Recently, we developed the chemistry of new phenolic resins by means of polymerization of designed phenol with aldehyde (a). In this work, we successfully synthesized a new linear phenolic resin 1' (b) from the trifunctional monomer 1. The 1H NMR spectrum shows an orthogonal orientation of the aromatic rings linked by methylene bridge (c). This is interesting as it indicates the possibility of a stereolegular polymer. Polymer 1' was colorless and showed thermoplasticity (Tg=110ßC) and film-forming property. 1' also has a high refractive (n=1.58) index and low birefringence (Dn << 0.0001) (d). Therefore, this type phenolic resin has considerable potential such as for optical materials, lens, transparent adhesives, and polymer blends. Polymer Preprints, Japan 2009, 58, 1364.

Highly Conductive and Transparent PEDOT/PSS Thin Films
Hu YAN*, Toshihiko JO, and Hidenori OKUZAKI
Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi
We have investigated the centrifuge effect on poly(3,4- ethylenedioxythiophene) / poly(4-styrenesulfonate) (denote PEDOT/PSS) films prepared by a spin-coating coupled with a solvent-treatment, by dynamic light scattering, scanning transmission electron microscopic, atomic force microscopic, and ultraviolet-visible spectroscopic measurements to determine electrical conductivity and optical transmittance properties. As a result, we have successfully prepared highly conductive (443 S/cm) and transparent (89% at wavelength of 520 nm) PEDOT/PSS thin films with thickness of 93 nm by the combination of three approaches, i.e., centrifuge, spin-coating, and solvent-treatment. The thin films are promising for wide applications to electronic devices such as touch screens and e-papers. Polymer Preprints, Japan 2009, 58, 1522. Polymer Journal 2009, 41 (12), in press.

Soluble Polyimide with Super Low Coefficient of Thermal Expansion Equivalent to Silicon
Yosuke YUKAWA
TOYOBO Co., Ltd.
We developed a soluble polyimide with super low coefficient of thermal expansion (CTE) of 3 ppm/K as same as that of Silicon. Polyimides are widely used as electronic materials due to their high heat-resistancy. However, their poor solubility leads to problems in the precursor handling which needs an elevated temperature treatment over 300C to dehydrate. Additionally the CTE mismatch between polyimides and substrates causes a serious influence in the industrial package process yield due to interconnecting breaks or delamination. This new polyimide exhibit a bulky and rigid structure, dissolved into NMP at 120C and didn't need any high temperature for dehydration. Then the thermal properties were excellent, Td over 500C and Tg over 400C. It is particular to note that the film showed the lowest CTE and the highest plane orientation in the known soluble polyimides (fig.1). Consequently our developed polyimide gave an eventual balance of heat-resistant, solubility and super low CTE as an electronic material and it would be promising for future thin silicon packaging materials. Polymer Preprints, Japan 2009, 58, 1643.

Discovery and Development of Transition Metal-Catalyzed Living Radical Polymerization
Masami KAMIGAITO
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University
Taming a radical polymerization into a controlled reaction has been difficult due to the highly reactive neutral growing radical species. We have discovered transition metal-catalyzed living radical polymerization using the reversible activation of the dormant species with a carbonÐhalogen bond and transforming it into the radical species based on the concept for living cationic polymerization. The metal-catalyzed system has now been applicable to various vinyl monomers with the use of a wide variety of transition metal catalysts and has enabled the precision synthesis of various well-defined polymers like block, random, gradient, end-functionalized, graft, and star polymers. We have further evolved living radical polymerization by additionally using special solvents or Lewis acids into stereospecific living radical polymerization for the simultaneous control of molecular weight and tacticity. Polymer Preprints, Japan 2009, 58, 2189.