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Vol. 60, No. 1, January(2011)

Degradation of Organic Compounds Using an Organophotocatalyst with p-n Junction Responsive to the Whole Spectrum of Visible Light
Keiji NAGAI
Division of Integrated Molecular Engineering, Chemical Resources Laboratory, Tokyo Institute of Technology

We have utilized the p-n junction, which consists of a metal-free phthalocyanine (H2Pc) and 3,4,9,10-perylenetetracarboxylbisbenzimidazole (PTCBI) for photocatalysis in gas and water phases. A tri-layer membrane of Nafion(50 mm)/ H2Pc(50 nm)/PTCBI(50 nm) was prepared using vapor deposition for the purpose of photocatalytic removal of trimethylamine (TMA). Nafion served as a mechanical support and adsorbent with optical transparency. TMA was concentrated and came in contact with the interface of p-type H2Pc. Holes generated at the p-n interface by visible light illumination were consumed to oxidize TMA, while electrons in the n-type PTCBI were consumed by a reduction concerning oxygen. The final product of the photocatalytic oxidation was CO2 whose molar amount was three times the initial one of TMA.
Polymer Preprints, Japan 2010, 59, 1169.

High Performance Ionic Liquid Chromatography
Yukinobu FUKAYA
Department of Biotechnology, Tokyo University of Agriculture & Technology
HPLC has been playing the indispensable part in separation, purification, and quantification in polymer chemistry. However, hardly soluble polymers have not been processed efficiently with HPLC with molecular liquid based eluents. Recently, we have prepared a series of novel high polar ionic liquids (ILs) as powerful solvents for scarcely soluble polymers. We propose a new HPLC method, with polar ILs as eluents, which we call high performance ionic liquid chromatography (HPILC). We successfully demonstrated the analysis of molecular weight distribution of a series of polysaccharides including nearly insoluble cellulose with HPILC. HPILC should open up a wide variety of opportunities in regard to processing of various bio and synthetic polymers including new classes of polymers whose properties are yet unknown.
Polymer Preprints, Japan 2010, 59, 2007.

Reversibly Thermoswitchable Luminescent Gold Nanoparticle Stabilized by a BODIPY-Terminated Water-Soluble Polymer
Atsushi NAGAI, Ryousuke YOSHII, Takeshi OTSUKA, Kenta KOKADO, and Yoshiki CHUJO
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University
Well-defined poly(N-isopropylacrylamide)s (PNIPAMs) with BODIPY in the terminal end were prepared by RAFT polymerization of NIPAM with BODIPY-chain transfer agent, and the in situ reduction of the RAFT-prepared polymers and HAlCl4 resulted in the formation of stable modified AuNPs with size distributions of about 10 nm in water solution. The AuNPs showed a decrease of intensities of their emission with increasing temperature (20->40oC). Shrinking of the distance between BODIPY units and the Au core in the AuNP across border LCST gives rise to the quenching of emission of BODIPY unit by FRET and the dye quenching of aggregated BODIPY units. Further, the emission/ quenching of AuNP occurs reversibly and efficiently, regardless of the heating and cooling cycle.
Polymer Preprints, Japan 2010, 59, 188.
Langmuir 2010, 26, 15644.

Dinaphthothiophene: A Novel High Refractive Index Material with High Thermal Stability
Yoko NAMBU
Institute of Technological Research, Kanagawa University, and Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University
We have found a novel optical material, dinaphthothiophene (DNpTh), showing a refractive index with the value of 1.808 at 539 nm, which is rarely observed in organic compounds in an amorphous state. DNpTh was obtained from racemic binaphthol in two steps. The oligomer, formed in the addition condensation reaction of DNpTh with paraformaldehyde, showed a high refractive index (n539=1.795) as well. Vinyl polymers obtained by radical polymerizations of vinyldinaphthothiophene also showed high refractive indices (homopolymer: n539=1.739; and copolymers: n539=1.72-1.73). These polymers, containing the DNpTh structure, exhibited high thermal stability and high transparency prospective for optical materials. We suppose that these excellent properties are the result of the unique structure of DNpTh, where the two skewed naphthalene rings orient out-of-plane and the thiophene ring is distorted to result in a lack of aromaticity.
Polymer Preprints, Japan 2010, 59, 290.

Dye-Sensitized Polymer/Fullerene Solar Cells
Satoshi HONDA1, Hideo OHKITA1,2, Hiroaki BENTEN1, and Shinzaburo ITO1
1Graduate School of Engineering, Kyoto University, 2PRESTO, Japan Science Technology Agency
We have demonstrated that the light-harvesting efficiency of bulk heterojunction solar cells based on blends of poly(3-hexylthiopene) (P3HT) and a fullerene derivative (PCBM) can be improved by incorporating a silicon phthalocyanine (SiPc) as the third component into the P3HT/PCBM interface. The incorporation of SiPc increased the short-circuit current (JSC) from 9.7 to 10.8 mA cm-2 because of the additional absorption of SiPc in the near-IR region, and hence improved the power conversion efficiency (PCE) from 4.0 to 4.5%, compared to those of the control P3HT/PCBM solar cell without SiPc. This is a simple and versatile method to boost the photocurrent of polymer/fullerene solar cells and therefore applicable to various donor/acceptor blends.
Polymer Preprints, Japan 2010, 59, 1250.

Highly Efficient All-Polymer Solar Cells
Daisuke MORI1, Hiroaki BENTEN1, Hideo OHKITA1,2, Shinzaburo ITO1, and Kunihito MIYAKE3
1Graduate School of Engineering, Kyoto University, 2PRESTO, Japan Science Technology Agency, 3Sumitomo Chemical, Co., Ltd.
We have fabricated highly efficient all-polymer solar cells based on blends of a poly(3-hexylthiophene) (P3HT) and a fluorene-based copolymer by spincoating. The device performance was significantly dependent on the spincoating solvent. The power conversion efficiency was improved from only 0.24% (JSC = 0.84 mA cm-2, VOC = 0.80 V, FF = 0.36) for o-dichlorobenzene to 2.0% (JSC = 3.94 mA cm-2, VOC = 1.19 V, FF = 0.42) for chloroform under AM1.5G simulated solar illumination at 100 mW cm-2. This is because the phase separation is appropriately suppressed by using a low-boiling solvent such as chloroform. The 2% efficiency is the highest among all-polymer solar cells reported so far.
Polymer Preprints, Japan 2010, 59, 1254.

Janus Hydrogel Particles
Daisuke SUZUKI
International Young Researchers Empowerment Center, Shinshu University
Polymer hydrogel particles have attracted much attention in material science due to their stimuli-responsive properties. In general, hydrogel particles are regarded as chemically and physically homogeneous. Here we report "Janus hydrogel particles", whose hemispheres are different from chemical and physical points of view. Using an oil/water interface of Pickering emulsions allows the introduction of a distributed functional group into the hydrogel particles. In addition, this methodology does not require an expensive apparatus and has the potential to be applied to a large-scale production of the particles. Interestingly, Janus hydrogel particles demonstrate a pH-responsive assembly into string structures as shown in the Figure. Such stimuli-responsive nano-structures may be applied in micro-actuators.
Polymer Preprints, Japan 2010, 59, 1462.
J. Am. Chem. Soc. 2007, 129, 8088.

Design of an Artificial Extracellular Matrix Protein with PMMA Binding Function
Naoki TANAKA
Department of Biomolecular Engineering, Kyoto Institute of Technology
We have generated an artificial extracellular matrix (ECM) by introducing a cell adhesion sequence to the recombinant protein. A RGD sequence was introduced to the C-terminus of Blocking peptide fragment (BPF), a fragment of a heat shock protein developed as the blocking reagent for the modification of the polymer surface property. To promote the binding function to isotactic poly(methyl methacrylate) (it-PMMA), a ELWRPTR (c02) sequence was introduced to the N-terminus of BPF-RGD. The high affinity of the c02-BPF-RGD sequence to a it-PMMA surface was confirmed by QCM analysis. The c02-BPF-RGD coated on it-PMMA surface exhibited excellent cell adhesion ability for a NIH3T3 cell line, indicating that this artificial ECM protein can be applied for the patterning of cell cultures on polymer surfaces.
Polymer Preprints, Japan 2010, 59, 1713.

Magneto-anisotropic Janus Particles Containing γ-Fe2O3 Nanoparticles
Hiroshi YABU1,2 and Toshihiko ARITA1
1Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University
2Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST)
Poly(styrene) (PS) stabilized magnetic nanoparticles were successfully synthesized by living radical polymerization from the surface of magnetic nanoparticles. Janus structured composite particles were prepared by using the Self-ORganized Precipitation (SORP) method. The good solvent (THF) was evaporated from the solution of PS stabilized γ-Fe2O3 nanoparticles and poly(isoprene) containing a poor solvent. The composite Janus nanoparticles responded to the magnetic field.
Polymer Preprints, Japan 2010, 59, 730.