竹岡 裕子

Lipase-catalyzed polymerizations of L-lactide were carried out in four kinds of ionic liquids (ILs) in order to investigate the effect of ILs on the conversion, molecular weight, and yield of the obtained poly(lactide) (PLLA). PLLA could be synthesized in ILs of 1-butyl-3-methylimidazolium ([C(4)mim]) except in [C(4)mim][N(CN)(2)]. While the number-average molecular weight (M-n) of the PLLA obtained in [C(4)mim][PF6] was below 4000 g mol(-1) and the yield was below 10%, the M-n and yield of the PLLA obtained in [C(4)mim][BF4] reached 55000g mol(-1) and 35%, respectively. The M-n values of PLLAs in the ILs were clearly higher than those of PLLAs obtained in bulk and in toluene (< 44000 g mol(-1)). The polymerization in the ILs proceeds even at lower temperatures as compared with that in bulk. The effect of lipase content on the M-n of PLLA was also investigated. When [C(4)mim][BF4] was used as the solvent, the highest M,, was obtained at a lipase content of 10wt%,. In the case of [C(4)mim] [NTf2], the most suitable lipase content depended on the polymerization temperature. [C(4)mim][BF4] was suitable to obtain higher molecular weight PLLA and higher polymer yield at lower lipase contents. Copyright (C) 2008 John Wiley & Sons, Ltd.

The mechanism of gas permeation in Nafion membranes for polymer electrolyte fuel cells has been investigated from the viewpoint of free volume. Three different samples, a membrane with ionic exchange capacity (IEC) = 0.92 meq/g, and recast samples with IEC = 0.92 and 1.00 meq/g were used after drying. Free volume was quantified using the positron annihilation lifetime (PAL) technique and gas permeabilities were measured for O-2 and H-2 as functions of temperature and relative humidity. Good linear correlations between the logarithm of the permeabilities at different temperatures and reciprocal free volume indicate that gas permeation in dry Nafion is governed by the free volume. Nevertheless permeabilities are much smaller than the corresponding flexible chain polymer with a similar free volume size due to stiff chains of the perfluoroethylene backbone. In highly hydrated Nafion above 60% relative humidity, where the O-2 permeability varies oppositely to the free volume, gas permeation proved to be controlled by the gradual increase in overall flexibility of the Nafion-water system. (c) 2008 Elsevier Ltd. All rights reserved.

AC-mode atomic force microscopy (AFM) and electrochemical methods were used to identify the proton conducting regions of Nation membrane. It was found that the surface of Nafion membrane was constructed of small hydrophobic granular domains and that protons passed through the hydrophilic regions formed in the interstices between those domains.

Poly(L-lactide) (PLLA) has been synthesized by ring-opening bulk polymerization Of L-lactide in porous hydroxyapatite (HAp) matrix without any additional catalyst, and this hybridizing process directly provided artificial bone materials. The obtained PLLA/HAp composites had enough mechanical properties with a bending strength of 53.7MPa, which was 2.3 times stronger than porous HAp, and showed excellent biocompatibility for clinical applications.

Two-dimensional layered perovskite compounds, (CnH2n+1NH3)(2)(CH3NH3)(m-1)PbmX3m+1 (n = 2, 3, 4, 6, and 10; X = Cl Br, and I; in = 1, 2, and 3) were systematically prepared. The influences of the barrier-size, halide species, and well thickness of the perovskite thin films on the quantum confinement structures were investigated. The layered perovskite films showed a strong and clear absorption peak due to excitons confined in inorganic quantum-wells. The exciton peak shifted to lower energy as the halide species was changed from Cl to Br and I. Furthermore, fine multilayer perovskite compound films were prepared by varying the spin-coating conditions.

We study the layer-by-layer assembly and properties of polyelectrolyte multilayers containing cationic and anionic polythiophene derivatives, poly-2-(3-thienyloxy)propyltriethylammonium chloride (PTPA), poly(thiophene-3-acetic acid) (PTAA), and poly(sodium-2-(4-methyl-3-thiehyloxy)ethane sulfonate) (P-SMTE). These polymers were synthesized by chemical oxidation with FeCl3 and soluble in aqueous media. Two types of multilayers have been prepared by sequential adsorption of polyanions and polycations on charged surfaces: PTPA/PTAA and PTPA/P-SMTE. The linear relationship of the UV-vis adsorption spectra and QCM observed in these multilayer systems indicated that each layer was successfully deposited to form layer-by-layer films. FT-IR results also revealed that the multilayer structure was formed by electrostatic interaction.

A regioregular polythiophene beating an optically active substituent at the 3-position of thiophene ring, Head-to-Tail poly(3-[2-((S)-1-methyloetyloxy)ethyl]thiophene) (HT-P(S)MOET), was synthesized using highly reactive zinc. HT-P(S)MOET had more than 95% Head-to-Tail coupling with a Mw of 3.72 x 10(4) (Mw/Mn = 1.20), as estimated by H-1-NMR spectroscopy and gel permeation chromatography. HT-P(S)MOET had strong negative Cotton effect at about 560 and 6 10 nm and positive Cotton effect at about 490 nm. The presence of circular dichroism effect shows that the chirality of side chains induces the optical activity in poly(thiophene) main chains. The Langmuir-Blodgett films of HT-P(S)MOET exhibited well-defined layer structure and unique optical properties.

Actuators based on hydrocarbon polymer electrolyte membranes having phosphoric acid groups were fabricated to investigate the correlation between the chemical properties and the actuation. The bending size and velocity of actuation were measured and compared with the values for fluorocarbon polymers, Nafion(R)-based actuators. The actuators were fabricated by coating polymer electrolyte membranes with gold using dichlorophenanthrolinegold (III) chloride. The actuators bent toward the anode when the applied voltage was over 1 kV. Nafion(R)-based actuators reached the maximum displacement size within 1 second, while the hydrocarbon polymer-based actuators took over 60 seconds. The difference in the velocity of actuation was caused by the difference in the proton conductivity of polymer electrolyte membranes. The maximum displacement size of hydrocarbon polymer-based actuators was nearly equal to that of Nafion(R)-based actuators.

A series of poly(thiophene)s, poly(3-(2-benzothiazolyl)thiophene) (PBTT) and poly(3-(2-benzothiazolyl)oxyethyl thiophene) (PBTOET), containing a benzothiazole moiety in the side chain have been synthesized by a cross-coupling reaction using Ni catalyst. PBTT and PBTOET were characterized by FT-IR and H-1-NMR spectra. Both polymers showed fluorescence peaks in the visible region. The HOMO and LUMO energies were estimated by cyclic voltammetry. PBTT was more suitable as a hole transporting material than PBTOET. The turn-on voltages of PBTT and PBTOET single layer EL devices were 5.0 V and 6.5 V, respectively.

Polycondensed thin films which had a high-ordered structure were fabricated from dicarboxylic acid and diamines using N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) as condensing agents by a self-assembly method. In this Study, adipic acid (ADA) or 9,11-docosadiyn-1,20-dicarboxylic acid (DDyDA) were selected for dicarboxylic acid, and 4,4'-diaminodiphenylmethane dihydrochloride (DAM) for diamine parts. UV-vis and quartz crystal microbalance (QCM) measurements were used to monitor the layer-by-layer deposition process. FT-IR reflection absorption spectroscopy (Fr-IR-RAS) was also carried out in order to confirm the polycondensation of monomers. These results indicated that 14 dicarboxylic acid and diamines were alternately deposited and polymerized with condensing agents on nano-scale. In addition, polydiacetylene network was successfully incorporated in DDyDA system by gamma-irradiation due to the high ordered structure. (c) 2004 Elsevier B.V. All rights reserved.

The layered perovskite. (RNH3)(2)PbX4 (R = alkyl group, X = halogen), which contained the fullerene ammonium derivative, N-methyl-2-(4-aminophenyl)-fulleropyrrolidine iodide (AmPF), in the organic layers, was fabricated as a thin solid film. X-ray diffraction measurement of the obtained films revealed that AmPF molecules were introduced to the organic layers, however, the obtained film was heterogeneous. The homogeneous perovskite films were fabricated by addition of dodecylammonium iodide as a supporting material to AmPF. It was found that the layered structures of two-dimensional perovskites changed depending on the rate of AmPF in the organic ammonium layers from the results of X-ray diffraction. UV-vis absorption spectra of the films were also changed by incorporation of AmPF molecules. By increasing the rate of fullerene, new peak at 560 nm was appeared while the exciton peak at 511 nm of the conventional layered perovskite diminished. This suggested that the exciton binding energy was transported from the exciton state of the conventional perovskites to the lower energy state formed by fullerene derivatives in the organic layers. (c) 2004 Elsevier B.V. All rights reserved.

New proton-conducting polymer electrolyte membranes having phosphoric acid groups have been systematically synthesized. These homopolymers and copolymers were prepared by a conventional radical polymerization and a copolymerization with acrylonitrile or styrene or similar materials. The phosphoric acid groups can be cross-linked by heat treatments at 100 &DEG; C, and hence their membranes showed excellent mechanical properties and chemical stability. Measurements of the water absorption and differential scanning calorimetry revealed that the copolymer membranes absorbed smaller amounts of water, which is freezing water under 90% RH, compared with the sulfonated polyelectrolyte membranes. The proton conductivity of the P-PHM membranes hydrated was measured to be 5.0 x 10(-3) S cm(-1) at 100 &DEG; C. This value was usually maintained up to 160 &DEG; C. Dried homopolymer membranes and copolymer membranes were also examined for the water absorption and proton conductivity. It was found that the copolymerization with acrylonitrile provided good film-forming properties, thermal stability, and useful control of the physical and electrochemical properties. &COPY; 2004 Elsevier B.V. All rights reserved.

A low-dimensional organic-inorganic perovskite compound, (C4H8N2H4)(2)PbBr6 center dot 2H(2)O, was synthesized from cyclic amines and PbBr2 by using a hydrothermal reaction. The versatile optical properties caused by the quantum confinement structure were investigated.

Well-ordered layered structures prepared by the self-assembly method using condensing agents better facilitate the gamma-ray polymerization of diacetylene units.

Two-dimensional and multi-layered perovskites, [NH3(CH2)(12)NH3] PbBr4 and [NH3(CH2)(12)NH3](CH3NH3)(n-1)PbnBr3n+1, with a quantum confinement effect have been naturally formed by intercalating lead bromide into organic alkyldiammonium bromide frameworks.

Phenethylammonium-based perovskites, which can be regarded as a semiconductor/insulator multiple quantum well consisting of lead halide semiconductor layers sandwiched between phenethylammonium insulator layers were prepared. To investigate the effects of the electronic state and the orientation of organic insulator layers on the optical properties of layered perovskites, fluorine substituted analogues were also prepared. The structure and optical properties were investigated by the XRD, UV-Vis absorption, and fluorescence measurements. The exciton absorption peak was shifted by the substitution of fluorine atoms in organic ammonium compounds. It became clear that the optical properties of two-dimensional perovskite compounds were controlled by the substitution of fluorine atoms. (C) 2004 Elsevier B.V. All rights reserved.

High-performance composites of poly(4-vinylpyridine-co-styrene) copolymer (P4VPy-St) and polyamic acids (PAA) were prepared by in-situ polymerization. High-performance composites could be obtained from a polymer pair that has an attractive interaction such as a hydrogen bonding interaction. The aggregation of the resulting polyimide (PI) took place easily in the P4VPy-St/PI composite film during the stepwise heat-treatment of the P4VPy-St/PAA composite film to convert PAA to PI. This was because of the disappearance of the carboxyl group due to the imidization of PAA. In this study, free carboxylic acid groups were introduced into the side chains of PI in order to improve the mechanical properties of P4Py-St/PI composites, and the carboxyl group content dependence of the tensile strength of the resulting composite films was investigated. The tensile strength of the resulting composite films increased with increasing carboxyl group content in PI. The hydrogen bonding interaction between the pyridine moiety in the P4VPy-St copolymer and the carboxyl group introduced into PI greatly enhanced both the compatibility and the tensile strength of the composite films.

Preparation and characterization of two-dimensional zirconium phosphonate derivatives in either crystalline or amorphous forms have been investigated. Composite zirconium phosphonates in single crystal phase have also been investigated and characterized by XRD and P-31-MASNMR. These compounds are lamellar structures comprising zirconium phosphates or organophosphonates. The hydroxyl groups or sulfomethyl groups are bonded through the phosphorous atoms to an inorganic framework made of oxygen and zirconium atoms. Compounds were characterized for their proton-conductivity as a function of temperature and relative humidity.

Poly(4-phenoxybenzoyl-1,4-phenylene) (PPBP), which has high thermal stability and mechanical properties, was phosphonated by the three-step reaction. The phosphonated PPBP (P-PPBP) was characterized by FT-IR, H-1-NMR, elemental analysis, and ICP emission spectroscopy. The thermal and electrical properties of P-PPBP were also investigated. The P-PPBP film containing 40 mol % phosphonic acid groups showed a proton conductivity of about 10(-4) S cm(-1) at 90 %R.H.

Formation of metal complexes from fullerene derivative and phthalocyanine (Pc) derivative was investigated. UV-Vis spectra of C-60 substituted with cyano group (C60CN) and phthalocyaninato iron(II) substituted with tert-butyl groups (FePcTB) showed charge transfer interaction in 1-chloronaphhtalene. The metal complex was synthesized by refluxing o-dichlorobenzene (ODCB) solution of C60CN and FePcTB. TOF-MS spectra indicated that the complex was composed of C60CN and FePcTB with mole ratio of 2/1.

Hybrid membranes consisting of butylsulfonated poly(2, 2'-m-phenylene-5, 5'-bibenzimidazole) (PBI-BS) and various apatite compounds were fabricated to improve the mechanical properties of PBI-BS, and their electrical and mechanical properties were investigated. The tensile strength of PBI-BS/apatite hybrid membranes was 1.7 times higher than that of PBI-BS membrane regardless of apatite compounds. The PBI-BS hybridized with Ca-10(PO4)(6)(OH)(2) and beta-Ca-3(PO4)(2) had conductivity of 10(-2) S-cm(-1). The hybridization with apatite compounds improved the mechanical properties of PBI-BS membranes without decreases in proton conductivity.

Copolymers of acid phosphoxyethyl methacrylate (PHM) and 2,2,2-trifluoroethylacrylate (TFEA) were synthesized in order to construct hydrophilic and hydrophobic domains as well as Nafion(R) membrane. Thermal decomposition temperatures of PHM-TFEA copolymers were about 250 degreesC, which showed sufficient thermal stability for polymer electrolyte fuel cells (PEFC). Water uptake of these copolymers was higher than that of Nafion 115 under low relative humidity, and proton conductivity of these polymers exhibited about 10(-3) S cm(-1) under 90% relative humidity at 80 degreesC.

Thin films of lead iodide based perovskites [p-F(C6H5)C2H4NH3](2)(CH3NH3)(m-1)PbmI3m+1 (m=1, 2) with different inorganic well thickness using p-fluorophenethylammonium as an organic cation were systematically prepared, and the structure and optical properties were investigated. X-ray diffraction patterns demonstrated that the spin-coated film was highly oriented with the c-axis perpendicular to the substrate surfaces and that the control of the inorganic layer thickness in layered perovskites can be achieved by changing the ratio of the two organic amines and lead iodide. When the feed ratio of p-fluorophenethylammonium salt, methylammonium salt, and lead iodide was 2:3.5:3, the bilayer structure was formed. Using p-fluorophenethylammonium instead of alkylammonium as an organic cation, the spin-coated film with high crystallinity was obtained.

Aromatic ammonium-based perovskites and fluorine substituted analogues were prepared. The effects of the electronic structures of aromatic ammonium containing fluorine on the optical properties of layered perovskites were investigated by the XRD, UV-Vis absorption, and fluorescence spectrum measurements. The absorption peaks were shifted by the substitution of fluorine atoms in organic ammonium compounds. It became clear that the optical properties of two-dimensional perovskite compounds were controlled by the substitution of fluorine atoms.

Regioregular poly(thiophene) derivatives with liquid crystal moiety, poly(3-[2-(4-fluorobenzyloxyethyl)]thiophene) (HT-PFBET) and poly(3-[2-benzyloxyethyl]thiophene) (HT-PBET), were synthesized using cross-coupling reaction according to the Rieke method. Thermochromism of HT-PFBET and HT-PBET was studied by electronic absorption measurements. HT-PFBET gave rise to a clear isosbestic point, while HT-PBET exhibited no isosbestic point with increasing temperature. This is due to a morphological effect induced by fluorine atoms.

Polymeric thin films which had a high-ordered structure were fabricated from adipic acid (ADA), 4,4'-diaminodiphenylmethane dihydrochloride (DAM), and N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) as condensing agents by a self-assembly method. UV-Vis and quartz crystal microbalance (QCM) measurements were used to monitor the layer-by-layer deposition process. FTIR reflection absorption spectroscopy (FTIR-RAS) was also carried out in order to confirm the polymerization of monomers. The surface morphology of the films was investigated with an atomic force microscope (AFM). These results indicated that ADA and DAM were alternately deposited and polymerized with condensing agents on nanoscale.

The template-guided enzymatic polymerization of conducting poly(aniline) particles was investigated. In order to clarify the role of templates in this polymerization, various template polymers such as poly(ethylene oxide) (PEO), polyvinyl alcohol) (PVA), polyvinyl pyrrolidone) (PVP), and poly(sodium 4-styrenesulfonate) (SPS) were used in this study. The enzymatic synthesis of poly(aniline) was successful with a stoichiometric amount of hydrogen peroxide and a catalytic amount of the enzyme (horseradish peroxidase). The chemical structures of template polymers provided difference in particle size of obtained poly(aniline).

Poly(3-(perfuorohexyl)thiophene) (PFHT) was synthesized from 2, 5-dibromo-3-(perfluorohexyl)thiophene via Grignard metathesis method. Obtained polymer was dissolved in a wide variety of organic solvents such as chloroform, tetrahydrofuran, and o-dichlorobenzene. Transition temperatures of PFHT were observed at 54 C due to melting of perfluorohexyl groups. Electron-withdrawing effect of C-F bonds and weak interaction among the side chains were observed as shorter maximum absorption wavelengths. Stable monolayers of PFHT were formed on a water subphase due to strong hydrophobicity and the weak interactions of the perfluorohexyl groups.

We report a new type of scintillator especially suitable for pulse-radiation detection. Thin films of organic/inorganic perovskite compound (n-C6H13NH3)(2)PbI4, which is characterized by a multiple quantum well structure, were bombarded by 2.0 MeV protons, and their radiation-induced emission spectra were obtained. A single and sharp emission peak due to an exciton was observed at the wavelength of 524 nm. This emission was clearly detected even at room temperature, and its quantum efficiency was very high. The line shape of this emission did not change, retaining its sharpness, and no other emissions appeared throughout the irradiation. The optical response of (n-C6H13NH3)(2)PbI4 is very fast. (n-C6H13NH3)(2)PbI4 is a promising scintillator material, meeting requirements not satisfied by conventional scintillators. (C) 2002 Elsevier Science B.V. All rights reserved.

Organic-inorganic semiconductor heterostructures have been successfully fabricated by incorporating a polydiacetylene backbone into layered perovskite compounds by photopolymerization. The gamma-ray irradiation caused polymerization of aminodiacetylene cations, RNH3+, where R=CH3(CH2)(13)C=C-C=CCH2, in the solid salts of (RNH3)(2)PbBr4.

Ultra-thin films of the two-dimensional layered perovskites [NH3(CH2)(12)NH3]PbX4 (X = Br, I) with the quantum confinement effect have been fabricated by a convenient self-assembly method.

A new type of organic-inorganic semiconductor heterostructure has been successfully fabricated by incorporating a polydiacetylene backbone into layered perovskite compounds by solid-state polymerization.

Thin films of layered perovskite compounds (CnH2n+1NH3)(2)(CH3NH3)(m-1)PbmBr3m+1 (m = 1, 2 and 3) were prepared by the spin-coating method from their DMF (N,N-dimethylformamide) solutions. The control of the inorganic layer thickness in layered perovskites can be achieved by changing the ratio of the two amines (CnH2n+1NH3/CH3NH3) The layered perovskite films showed a strong, clear exciton absorption peak at room temperature due to their large exciton binding energy. With increasing numbers of inorganic layers, a red shift of the exciton absorption was observed due to the decrease in transfer energy. X-ray diffraction patterns clearly demonstrated that the spin-coated film was highly oriented normal to the surface, which is consistent with 'mono', 'bi', and 'tri' layer structures, respectively. The effect of the alkyl chain length of the organic part was also investigated. (C) 2000 Elsevier Science Ltd. All rights reserved.

Langmuir-Blodgett films were fabricated from mixed monolayers containing stearic acid (SA) and various Head-to-tail poly(3-alkylthiophene)s (HT-PATs:alkyl = hexyl (HT-PHT), decyl (HT-PDT), octadecyl (HT-PODT)). The HT-PATs could form stable monolayers on the air-water interface with stearic acid, and could be deposited onto solid substrates as Y-type films by vertical dipping method. The structure of HT-PATs/SA LB films were investigated by transmission and reflection-absorption FT-IR measurements. By comparison of transmission and reflection FT-IR spectra, the tilt angles of alkyl side-chains of HT-PATs could be estimated. These results shows that self-organized properties and molecular orientation of HT-PATs were affected by the length of alkyl-side chains. HT-PDT was found to form more planar conformation because of the optimized length of alkyl-side chains.

We examined the self-organized properties of regioregular poly(3-alklylthiophene)s(HT-PATs) in Langmuir-Blodgett(LB) films by X-ray diffraction and FT-IR measurements. The HT-PATs showed self-organized properties due to their stereoregularity. The pendent decyl groups of HT-PDT formed more planar conformation and interdigitated structure. Electrical conductivities of doped HT-PATs/SA LB films were dramatically improved compared with random PATs, and HT-PDT films showed the highest in-plane conductivities among HT-PATs LB films.

We synthesized an optically active regioregular poly(3-substituted thiophene), head-to-tail poly(3-[2-((S)-2-methylbutoxy)ethyl] thiophene) (HT-P(S)MBET), according to a modified Rieke method. The HT-P(S)MBET was an optically active polymer with the HT linkage of larger than 93%, as estimated by NMR. The mixed monolayers of the polymer and stearic acid (SA) were found to be stable at the air-water interface and could be deposited onto solid substrates as Y-type films by the vertical dipping method. These Langmuir-Blodgett (LB) films exhibited well-defined layer structures and unique optical properties. The electrical conductivities of the LB films with and without doping of SbCl5 were about 10(-1) and 10(-5) S/cm, respectively. (C) 1998 Elsevier Science S.A. All rights reserved.

Novel Langmuir-Blodgett (LB) films were fabricated from mixed monolayers containing stearic acid and various poly(3-alkylthiophene)s, which contained almost 100% head-to-tail couplings. The LB films exhibited well-defined layered structures and self-organized properties of the regioregular polymers. The molecular organization, the layered structures and the electrical properties depended on the regioregularity and the length of the alkyl side chains of the regioregular polymers. The regioregular polymers have considerably improved the electrical conductivity and the third-order optical non-linearity. (C) 1998 Elsevier Science S.A. All rights reserved.