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Vol. 59, No. 10, October(2010)

Cooperative Hydration of Poly(N-isopropylacrylamide)
Fumihiko TANAKA
Department of Polymer Chemistry, Kyoto University

Sharpcollapse and the flat LCST cloud-point lines observed in aqueoussolutions of poly(N-isopropylacrylamide) (PNIPAM) are shown to becaused by the cooperative hydration (interaction between the adjacentbound water molecules) within the theoretical framework of associatingpolymer solutions. We examined the applicability of the concept ofcooperative hydration for PNIPAM in water in the absence and presenceof a tension, and for PNIPAM in a mixed solvent of water and a secondwater-miscible solvent. The tension-elongation curve of a hydratedchain shows a flat plateau corresponding to reeling out of the globulesin the transition region. The reentrant coil-globule-coil transitionand cononsolvency effect on the phase separation in the mixed solventof water and methanol are shown to be caused by the competitivepolymer-water hydrogen bonding and polymer-methanol hydrogen bonding.Polymer Preprints, Japan 2010, 59, 25.

Postfunctionalization of Conjugated Polymers by Alkyne-Acceptor Click Chemistry
Global Edge Institute, Tokyo Institute of Technology, and PRESTO, JST
Alkyne-acceptorclick chemistry is the study of versatile reactions which producedonor-acceptor chromophores in remarkably high yields without any sideproducts. Ferrocene-containing poly(aryleneethynylene)s, prepared bythe Sonogashira polycondensation between diiodoferrocene anddiethynylbenzene derivatives, were subjected to the reaction withtetracyanoethylene (TCNE). Although the reaction yield was moderate (upto 75%), there were no side reactions. The remaining TCNE was readilyremovable by sublimation and the desired donor-acceptor alternatingconjugated polymers were obtained in a one-step atom-economicalfashion. The donor-acceptor polymers have the following features: anenhanced thermal property, charge-transfer (CT) bands in the entirevisible region, and redox activities in both the anodic and cathodicdirections. Polymer Preprints, Japan 2010, 59, 104., Polymer Preprints,Japan 2009,58, 2761.

Organic Polymer-Assisted Formation of Microspheres Consisting of Pristine Fullerenes
Organic Nanomaterials Center, National Institute for Materials Science
Assemblingp-conjugated molecules into larger superstructures is attractive as aroute to functional materials and as a potential approach forcontrolling their morphology when used in devices. Utilizing aporphyrin polymer to control the assembly of fullerenes throughsupramolecular interactions, we fabricated microspheres consisting ofnanoplates of pristine fullerenes. The size of the microspheres can bealtered by changing the concentrations of the two individual solutions.We also showed that very little of the porphyrin polymer is present inthe final spheres. We propose that the polymer directs the fullerenesto form the microspheres through microdisks and a mechanism resemblesbiomineralization. Polymer Preprints, Japan 2010, 59, 107.

Ideal Copolymerization of Lactide with e-Caprolactone
Azusa AKITA, Ryohei ISHII, and Nobuyoshi NOMURA
Lab. Polym. Chem., Grad. Sch. Bioagr. Sci., Nagoya University
Inthe copolymerization of racemic/homochiral lactide (LA) ande-caprolactone (CL), LA is selectively polymerized first in general,followed by CL. Therefore, only tapered/blocky copolymer is obtainedusing conventional catalysts. We recently found that the bulkiersubstituents of homosalen-Al complexes reduced the polymerization rateof LA but increased that of CL in each homopolymerization. Thesecontrastive substituent effects encouraged us to investigate thecopolymerization of LA with CL, and we discovered that theiPr3Si-substituted homosalen-Al complex was an excellent catalyst forthe practically ideal copolymerization of LA with CL. In the idealcopolymerization, we can freely synthesize the polymers bearingvirtually homogeneous properties on the molecular scale betweenpoly(CL) and poly(LA) by changing the initial comonomer ratios.J. Am.Chem. Soc. 2010, 132, 1750., Polymer Preprints, Japan 2010, 59, 321.

Construction of Photo-Responsive Organic Nanotubes Aiming at Controllable Guest Release
Naohiro KAMETA, Asuka TANAKA, Haruhisa AKIYAMA, Hiroyuki MINAMIKAWA, Mitsutoshi MASUDA, and Toshimi SHIMIZU
Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST)
Novelamphiphiles, which have an azobenzene as a photo-responsive moiety andoligoglycine as an intermolecular hydrogen bonding moiety, proved toself-assemble in water to form nanotubes with a 20 nm inner diameter. The azobenzene moiety of the nanotubes showed a reversible trans-cisisomerization by UV and visible irradiations within 15 min even thoughthe nanotubes consist of solid-state bilayer membranes. The trans tocis isomerization induced a remarkable morphological change from thenanotubes to nanofibers. The photo-responsive morphological changestrongly promoted a release of encapsulated guests in the nanotubes toa bulk solution. The photo-responsive nanotubes will lead to smartnano-containers and -carriers useful for new types of drug-delivery andmedical diagnosis systems. Polymer Preprints, Japan 2010, 59, 252.

Selective Synthesis of Flower-Shaped Polymers by Living Cationic Polymerization
Shokyoku KANAOKA, Aya YANAGISAWA, Naoto YAGI, and Sadahito AOSHIMA
Graduate School of Science, Osaka University
Flower-shapedpolymers were selectively obtained from the linking reaction of livingpolymers, prepared using a bifunctional initiator, with a small amountof a divinyl ether based on living cationic polymerization. Reactionconditions such as solvents, concentrations of living polymers, andtypes of divinyl ethers were critical for producing well-definedpolymers. Relatively narrow molecular distributions were attained onlyat low concentrations in toluene in the presence of 1,4-dioxane. 1H NMRanalysis indicated that the terminal end groups of the starting linearpolymers were within the crosslinking core of the flower-shapedpolymers. The loop structure was demonstrated by very similar molecularweights before and after bond scission of initiator moieties in theloop chains.Polymer Preprints, Japan 2010, 59, 138.

Helical Crystals of Poly (ester imide)
Miki NAKAGAWA1, Kanji WAKABAYASHI1, Yuko MAKI1, Tetsuya UCHIDA2, Shinichi YAMAZAKI1, and Kunio KIMURA1 1Graduate School of Environmental Science, Okayama University
2Graduate School of Natural Science and Technology, Okayama University
Helical crystals of aromatic poly (ester imide) were successfully prepared by crystallization of oligomers during the polymerization of N-(4-carboxphenyl)-4-acetoxyphthalimide. The polymerization was performed at 260-330oC at a low concentration of monomers in an aromatic solvent without stirring. Although the polymerization at 260oC gave plate-like crystals, that at 280-330oC afforded the highly crystalline helical crystals with ca. 240 nm in width and ca.3.6 mm in length. The molecules oriented along the long axis of the helical crystals. The helical pitch was controllable from 321 nm to 1.29 mm by changing the temperature. Increasing temperature resulted in continously longer pitch. The morphology of the poly(ester imide) was drastically changed by the structure of the monomer and the helical crystals were not formed from N-(4-acetoxyphenyl)-4-carboxyphthalimide in which the imide linkage is reverse. Polymer Preprints, Japan 2010, 59, 225.

Planar Chiral [2.2]Paracyclophanes and Their Conjugated Polymers
Yasuhiro MORISAKI, Lin LIN, and Yoshiki CHUJO
Graduate School of Engineering, Kyoto University
It is well-known that mono- or disubstituted [2.2]paracyclophane compounds have planar chirality due to the restricted rotation of stacked benzene rings. Several optically active pseudo-ortho-[2.2]paracyclophane compounds have been thus far prepared; however, their practical synthetic methods have been limited. In this research, we successfully carried out the optical resolution of the disubstituted pseudo-ortho-[2.2]paracyclophane compound. On the basis of this method, we prepared optically pure (Rp)- and (Sp)-pseudo-ortho-diethynyl[2.2]paracyclophanes as monomers. Thus, we synthesized optically active through-space poly(arylene-ethynylene)s consisting of planar chiral [2.2]paracyclophane units in the main chain. The obtained polymers exhibit circularly polarized luminescence in the visible blue region. Our approach will lead to divergent formation of optically active through-space conjugated polymers as well as carbon rich compounds. Polymer Preprints, Japan 2010, 59, 294.

Control of Temporal Structures for Polymer Particles
Daisuke SUZUKI* and Ryo YOSHIDA
International Young Researchers Empowerment Center, Shinshu University
Polymer particles have increasingly found important use as building blocks for the creation of well-organized assemblies that promise to realize advanced soft materials. Different from simple stimuli-sensitive polymer particles, we have reported autonomously oscillating particles by constructing chemical cycle into them. The particles did show not only a swelling/deswelling oscillation, but also a dispersing/ flocculating oscillation near their phase transition temperature, which was confirmed by optical transmittance, redox potential, and viscosity measurements. The particles may be used as next generation, smart materials. Polymer Preprints, Japan 2010, 59, 677.