陸川 政弘

Novel lead iodide-based layered perovskite compounds, which contain fullerene derivatives, N-methyl-2-(4-ammoniumphenyl)-fulleropyrrolidine iodide (AmPF) and N-(n-dodecyl)-2-(4-ammoniumphenyl)fulleropyrrolidine iodide (C12AmPF), in their organic layers were fabricated as thin solid films by spin-coating. The XRD profiles showed that (AmPF)Pbl(4) molecules were arranged in a closer-packing form, compared with (C12AmPF)Pbl(4). The photoluminescence spectra of thin films suggested the presence of energy transfer between C(60) moiety and lead(II) iodide layers, which led to the disappearance of fluorescence peak at 517 nm and the appearance of a new fluorescence peak at 780 nm.(AmPF)Pbl(4) and (C12AmPF)Pbl(4) films exhibited photoconductivity when ultraviolet light was irradiated, and the photocurrent values with applying 1.0 V bias voltage were 1.77 mu A and 1.48 x 10(-2) mu A, respectively. (C) 2009 Elsevier B.V. All rights reserved.

The relationships between morphology and proton conduction for Nafion membranes and hydrocarbon-type proton exchange membranes, namely, sulfonated poly(arylene ether ether ketone) (S-PEEK) and sulfonated poly(arylene ether sulfone) (S-PES), were investigated by small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). The direct simultaneous observation of surface morphology and active regions of proton conduction on membranes by combined high-resolution AFM phase imaging and an electrochemical technique at controlled humidity provided significant morphological information, particularly for the hydrocarbon-type membranes that exhibit few or no features on SAXS profiles. For the Nafion membranes, the active proton paths became denser and congregated with each other at over 60% RH, resulting in the formation of well-connected networks. For the hydrocarbon-type membranes, however, only the relatively small and dispersed proton paths were observed, which showed no significant change even as water content increased. We have demonstrated that the differences in microscopic morphology between the Nafion and hydrocarbon-type membranes are associated with the differences between their macroscopic proton conductivities. (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.

Poly(L-lactide) (PLLA), and poly(ε-caprolactone) (PCL) have received much attention in medical applications because of their biocompatibility and biodegradability. Both PLLA and PCL have insufficient mechanical properties for tissue engineering scaffolds. In this study, poly(L-lactide-co-ε- caprolactone) (PLCL) copolymers were synthesized by ring-opening polymerization of L-lactide (LLA) and ε-caprolactone (ε-CL) in the presence of Pseudomonas lipase (lipase PS) as a catalysis. PLCLs with different LLA-ε-CL ratios were synthesized, and the product was characterized by 1H NMR, gel permeation chromatography (GPC), thermal gravimetry (TG), and differential scanning calorimetry (DSC). The number of molecular weight of PLCL increased with increasing reaction time. The molar fraction of L-lactide in PLCL polymerizing for 9days was equals to the feed ratio of L-lactide. In addition, osteoblast-like MC3T3-E1 cells were cultured on PLLA, PCL, and PLCL cast films.

Hydroxyapatite (Ca10(PO4)6(OH) 2 HAp) has been used as a biomaterial due to its similarity to bone mineral in structure, composition, and its good biocompatibility to human tissue. Recently, much attention has been focused on the combination of HAp with biodegradable polymers to improve the mechanical properties of HAp. In this study, we tried to fabricate poly(lactic-co-glycolic acid) (PLGA)/HAp hybrid materials by the in-situ polymerization in porous HAp ceramics with lipase MML as a catalyst. The effect of feed ratio of L(-)-lactide in PLGA on their biocompatibility was examined. The result of cytotoxicity tests showed that both the adherability and the multiplication of osteoblast-like MC3T3-E1 decreased with adding lactic acid or glycolic acid, because the pH was not suitable for the cell. SEM images showed that osteoblast-like MC3T3-E1 cells were cultured on the composites.

Direct methanol fuel cells (DMFCs) are promising candidates for the application of portable power sources due to the advantage of simple system design and operation. Perfluorosulfonic acid membranes such as Nafion® are widely used as polymer electrolyte membranes in DMFCs because of good chemical and mechanical properties as well as their high proton conductivity. However, there is a few drawbacks including high cost and high methanol permeability. In this study, novel sulfonated poly(4-phenoxybenzoyl-1,4-phenylene) (S-PPBP) - poly(arylene ether ketone-6F) (PAEK-6F) block copolymer (S-PPBP-b-PAEK-6F) was synthesized to decrease the methanol permeability, and the properties of the S-PPBP-b-PAEK-6F membrane were investigated. The S-PPBP-b-PAEK-6F membrane had good thermal stability and showed higher mechanical properties than that of the S-PPBP membrane. The proton conductivity of S-PPBP-b-PAEK-6F membrane achieved 1.04 × 10-1 S/cm at 80°C, 90 %RH, which is comparable to that of Nafion®115 membrane. The methanol permeability of S-PPBP-b-PAEK-6F membrane is 1.09 × 10-6 cm2/s, which is about half than that of S-PPBP and Nafion® membranes.

Biocompatible ceramic, hydroxyapatite (Ca10(PO4) 6(OH)2 HAp), was widely used as substitute material of clinical implants, the mechanical properties of pure HAp, however, was different from that of natural bone. Recently, the composites of biocompatible ceramics and biodegradable polymers were expected as biomaterials for medical applications. In this study, HAp was hybridized with poly(L-lactide) (PLLA) in order to achieve materials with good mechanical properties similar to natural bone. PLLA/HAp composites were fabricated by in-situ polymerization of L-lactide in porous HAp ceramics at 130°C for 7 days. The composites showed excellent bending strength and fracture toughness. In addition, osteoblast-like MC3T3-E1 cells were cultured on the composites in order to investigate their biocompatibility. The rate of multiplication of MC3T3-E1 cells on the PLLA/HAp composites was comparable to that on pure HAp. These results suggested that the introduction of PLLA into porous HAp seem to have positive effects on the application for bone tissue engineering.

Hydrocarbon based polymer electrolyte, sulfonated poly(4-phenoxybenzoyl-1, 4-phenylene) (S-PPBP), is one of the most promising materials for an electrolyte of polymer electrolyte fuel cells. S-PPBP shows high proton conductivity and excellent thermal stability, but the low mechanical properties and poor dimentionaol stability at high water uptakes limit their commercial applications. In this study, m-acetylphenylene (MAP) was introduced to the poly(p-phenylene) backbone to improve the mechanical properties of S-PPBP. Poly(4-phenoxybenzoyl-1,4-phenylene-co-m-acetylphenylene) (P(PBP-co-MAP)) was synthesized by Ni(0) catalyzed coupling reaction. Sulfonation of P(PBP-co-MAP) was performed by stirring of P(PBP-co-MAP) in concentrated sulfric acid. The weight-average molecular weight of sulfonated P(PBP-co-MAP) (S-P(PBP-co-MAP)) was 55,000, and the ion exchange capacity of S-P(PBP-co-MAP) was 2.84 meq g -1. Proton conductivity of the S-P(PBP-co-MAP) membrane was 1.1 × 10-1 S cm-1 at 80°C under 90%RH, which is comparable to that of Nafion®15 membrane. Water uptake of the S-P(PBP-co-MAP) membrane was 64% at r.t. under 100%RH that is lower than that of the S-PPBP membrane.

As one of the most important biodegradable and biocomptible polymers, poly(L-lactide) (PLLA) is widely studied for promising biomedical materials. Enzymatic polymerization of PLLA is a green method for chemical synthesis, however, the process usually needs many hours, and can not provide high molecular weight PLLA. In this study, we investigated the application of microwave technology to overcome those drawbacks. The polymerization of L-lactide was carried out with various lipases as catalysts and the results were compared with conventional heating method. The product was characterized by FT-IR, TOF-MS, and 1H NMR. In microwave heating method, the conversion of L-lactide was higher than the conventional heating method. 1H NMR spectra showed the rapid ring-opening reaction of L-lactide, suggesting masses of oligomer components formation under the microwave heating. Molecular weight of microwave-synthesized PLLA was comparable to that of conventional heating method. Therefore, the microwave heating is applicable to enzymatic polymerization of PLLA. Lipase CALB showed the best enzymatic activity under both the conventional and microwave heating.

Polythiophene derivatives show interesting optical and electrical properties. Especially, optically active polythiophene derivatives have attracted much attention because of their unique structures and organization properties. These properties are greatly dependent on the degree of regioregularity, which can be defined as the percentage of Head-to-Tail couplings. In this study, optically active regioregular polythiophene, HT-PMOETs (HT-P(S)MOET and HT-P(R)MOET) were synthesized and applied to EL devices. Both HT-PMOETs had about 95 % Head-to-Tail couplings and showed large Cotton effects in a poor solvent. Multi-layer EL devices with the configuration of ITO/PEDOT:PSS/HT-PMOET/Alq3/Al-Li emitted at 750 nm, indicating that HT-PMOETs worked as an emission layer.

Polycarbonate (PC) is one of super engineering plastics with good transparency and impact-resistance. However, the surface hardness of PC is insufficient for optical and practical applications. Poly(benzoyl-1,4-phenylene) (PBP) has good mechanical properties and transparency. In this study, we synthesized a novel copolymer, poly(benzoyl-1,4-phenylene-co-4-fluorobenzoyl-1, 4-phenylene) (PBP-co-PFBP) using Ni(0) catalysts. The blend films comprised of PC and PBP-co-PFBP with various contents were fabricated by a solvent casting method. All PC/PBP-co-PFBP blend films showed good optical transmittance no less than 85 % at 700 nm. Surface hardness of the PC/PBP-co-PFBP blend films was estimated by optical transmittance at 700 nm before and after abrasion by using a coating tester with steel wool. The results of hardness tests showed that surface hardness of the PC/PBP-co-PFBP blend films increased with increasing PBP-co-PFBP ratio.

Electrode electrolyte (binder) materials in polymer electrolyte fuel cells (PEFCs) are usually fluorocarbon polymers. By using the hydrocarbon polymers as the binder, the environmental problems may be solved, and the development of high-temperature PEFCs with low cost may be possible. In this study, sulfonated poly(4-phenoxybenzoyl-l,4-phenylene) (S-PPBP) was synthesized, and S-PPBP was used for the binder. The ion exchange capacities of S-PPBPs were estimated as 2.83 (Mw=85,000) and 2.78 (Mw=168,000) meq/g by titration. The performance of the MEA with the S-PPBP (Mw= 168,000) binder and a Nafion®115 electrolyte membrane was higher than that with the S-PPBP (Mw=85,000) binder. The maximum power density (122 mW/cm2) was observed when the both amounts of Pt and S-PPBP (Mw= 168,000) were 1.0 mg/cm2 (S-PPBP/Pt=1.0). As a result of the PEFC performance and SEM images, the most suitable composition of the electrode was found to be Pt/S-PPBP=1.0.

Polymer electrolyte fuel cell (PEFC) is one of the most promising candidate systems for novel electric generation. Recently, hydrocarbon polymer electrolytes have received much attention due to lower cost, compared with perfluorinated polymer electrolytes such as Nafion®. Polyhedral oligomeric silsesquioxane (POSS) contains an inorganic Si8O12 core surrounded by organic substitutes. It has been reported that aggregation of POSS in various polymer materials improved the mechanical and thermal properties of the polymers. In this study, POSS was introduced into polymer electrolyte materials in order to control the water absorption properties. Phosmer (PHM)-co-POSS and sulfoneted polystyrene-co-POSS were synthesized, and various properties such as X-ray diffraction, proton conductivity, and dimensional change were investigated. The XRD pattrens indicated that POSS in both the copolymers crystallized in hexagonal crystalline as well as POSS macromonomers. P(PHM-co-POSS) and S-P(St-co-POSS) showed the maximum proton conductivity of 3.2 × 10-2 and 4.7 × 10-2 S/cm at 80°C and 90 %R. H., respectively. Dimensional changes were investigated by immersing the sample membranes into water at 80°C. The swelling ratio of S-P(St-co-POSS) membrane was lower than that of sulfonated polystyrene (SPS) membrane.

Sulfonated poly(4-phenoxybenzoyl-1,4-phenylene) (S-PPBP) is an excellent polymer electrolyte having a high proton conductivity. However, S-PPBP has a poor dimentional stability and difficulty in fabricating flexible films due to the rigid main chains. On the other hand, poly(ether sulfone) (PES), which has a flexible structure, shows a good dimension stability. In this study, two kinds of Cl terminated PES oligomers (Cl-PES24, Cl-PES12) were synthesized. The number of repeating unit of Cl-PES24 and Cl-PES12 was calculated by 1H NMR to be 38 and 17, respectively. A novel PPBP-PES block copolymer (PPBP-b-PES) was synthesized via Ni(0) coupling reaction of 2,5-dichloro-4'-phenoxybenzophenone and Cl-PES12. The obtained block copolymers were characterized by FT-IR, 1H, 13C NMR, and elemental analysis. PPBP-b-PES had Mn=38,100, Mw=106,800, and PDI=2.80, as determined by GPC analysis calibrated with polystyrene standards. The same copolymerization with Cl-PES24 could hardly proceed.

Superhydrophobic surfaces with a water contact angle over 150° are expected to be applied on medical and environmental fields. In this study, we fabricated superhydrophobic thin films using poly(tetrafluoroethylene) (PTFE) particles and various F-containing copolymers by a conventional self-assembly method. Contact angles of water on both self-assembled (SA) films increased relative to number of bilayers. However, these SA films didn't show superhydrophobicity as a PTFE/PPHP films.

Hydroxyapatite (Ca10(PO4)6(OH) 2 HAp) has biocompatibility, but its mechanical strength is not enough to apply to organism tissue substitution materials. In this study, HAp was hybridized with PLLA in order to achieve biocompatible materials with high toughness. HAp/PLLA composites were fabricated by polymerizing L-lactide with lipase CA at 130°C for 7 days in porous HAp ceramics. Moreover, it was tried to increase the number of hydroxyl groups on the surface of HAp by the hydrothermal treatment, and the relationship between PLLA contents of composites and their mechanical properties were investigated. As the pH of the hydrothermal treatment increased, the porosity of composites decreased, whereas the mechanical properties of bending strength and fracture toughness increased.

Poly(L-lactide) (PLLA), which is an important material for medical applications, are usually synthesized by metal catalysts. Enzymatic polymerization with lipase receives much attention as an example of a new methodology of polymer syntheses in the context of green chemistry. There are some ambiguous parts in enzymatic polymerization mechanism. In this study, PLLA was synthesized by lipase-catalyzed polymerization with various water contents, or without lipase. The effect of lipase and water content on the conversion, the molecular weight, and the crystallinity of the obtained PLLA were investigated. In the case of lipase-catalyzed polymerization, the conversion of L-lactide were constant independent of the water volume, and the molecular weight of PLLA decreased with the water volume. On the contrary, the conversion of L-lactide decreased with the water volume, and the Mw of PLLA synthesized without lipase were constant independent of the water volume.

Alternating copolymer of chiral thiophene and non-substituted thiophene, poly(3-[2-((S)-(+)-1-methyloctyloxy)ethyl]-2,2'-bithiophene) (P(S)MOET-T), and the regioregular chiral polythiophene, head-to-tail poly(3-[2-((S)-(+)-1- methyloctyloxy)ethyl]thiophene) (HT-P(S)MOET), were synthesized by Rieke method. The molecular weight of P(S)MOET-T and HT-P(S)MOET were MW = 28,000 and 38,000, respectively. The head-to-tail ratios of P(S)MOET-T and HT-P(S)MOET were estimated to be 95 % by 1H NMR. Bandgaps of P(S)MOET-T and HT-P(S)MOET, which were calculated from UV-Vis absorption spectra, were 1.94 eV and 1.83 eV, respectively. Cyclic voltammetry of P(S)MOET-T and HT-P(S)MOET cast films were measured in a 0.1 M Bu4NBF4/acetonitrile solution. Oxidation onset potential of P(S)MOET-T, HT-P(S)MOET were 0.45 V and 0.70 V, respectively.

Hydrocarbon polymer electrolytes based on poly(phenylene), sulfonated poly(4-phenoxybenzoyl-1,4-phenylene) (S-PPBP), shows high proton conductivities and excellent fuel cell performances. However, their mechanical properties at high water uptakes and chemical stability were insufficient. In this study, we tried to synthesize high molecular weight PPBP in order to improve chemical stability and mechanical properties. Various synthesis conditions including catalysts, ligands, solvents, and reaction temperatures were investigated. High molecular weight polymers were only obtained by using NiCl2(PPh 3)2 as a catalyst and PPh3 as a ligand. NMP was the most effective solvent for PPBP synthesis. Under these reaction conditions, reaction temperature was an important factor. At 65°C, the highest molecular weight were obtained.

Hydroxyapatite (Ca10(PO4)6(OH) 2 HAp) has been used as a biomaterial due to its similarity to bone mineral in structure, composition, and its good biocompatibility to human tissue. Recently, much attention has been focused on the combination of HAp composites with biodegradable polymers to overcome the problem of poor mechanical properties of HAp. In this study, we tried to fabricate poly(lactic-co-glycolic acid) (PLGA)/HAp by the in-situ polymerization in porous HAp with lipase as a catalyst. The effect of molar ratio of L-lactide in PLGA (FL) on their mechanical properties was examined. The maximum bending strength and the fracture toughness of the hybrids were 91.1 MPa and 1.30 MPa·m1/2 at FL = 0 %, respectively. The mechanical properties of composites increased with decreasing the FL of PLGA, indicating that the properties of the hybrids could be controlled by the crystallinity of the polymer in HAp.

Poly(L-lactide) (PLLA), which is an important material for medical applications, has been synthesized by metal catalysts. Enzymatic polymerization using lipase receives much attention as an example of a new methodology of polymer syntheses in the context of green chemistry. High molecular weight PLLA can not be obtained by enzymatic polymerization in comparison with the metal catalyst synthesis. Water within L-lactide and lipase affects the enzymatic polymerization activity. In this study, PLLA was synthesized by lipase-catalyzed polymerization with various water contents, and the effect of water content on the conversion and the molecular weight of the obtained PLLA were investigated. The molecular weight of PLLA decreased as the water volume increased, while the conversion of L-lactide was constant independent of the water volume. The effect of lipase content on the molecular weight of PLLA was also investigated. By synthesizing with additional water, the molecular weight of PLLA decreased with decreasing lipase content. Without additional water, the molecular weight of PLLA increased with decreasing lipase content.

We reported that sulfonated poly(4-phenoxybenzoyl-1,4-phenylene) (S-PPBP) showed high proton conductivities and excellent fuel cell performances. In this study, polycyclic aromatic moiety, anthraquinone, was copolymerized with PBP in order to improve the mechanical properties of S-PPBP. Poly(4-phenoxybenzoyl-1,4- phenylene-co-1,5-anthraquinone) (P(PBP-co-ANQ)) was synthesized by Ni(0)-catalyzed coupling reaction. The copolymerization ratio of P(PBP-co-1,5ANQ) was calculated as PBP: 1,5ANQ =17:1 by the 1H NMR spectrum. The glass transition point of poly(4-phenoxybenzoyl-1,4-phenylene-co- 1,5-anthraquinone) (P(PBP-co-1,5ANQ)) was 158 °C, which was 5 °C higher than that of the PPBP Sulfonated P(PBP-co-1,5ANQ)s (S-P(PBP-co-1,5ANQ)s) were obtained by the reaction of P(PBP-co-1,5ANQ) with concentrated sulfuric acid at 10, 15, 20, and 25 °C. The weight-average molecular weights of the all the S-P(PBP-co-1,5ANQ)s determined by GPC were about 85,000 - 110,000. The conductivity of the S-P(PBP-co-1,5ANQ) membranes achieved about 10-1 S cm-1 at 90 %RH.

Novel proton conducting electrolyte films consisting of polyhydroxy hydrogen sulfated fullerene (PHSF) and sulfonated poly(ether ether ketone) (S-PEEK) were fabricated. Structural stabilities, chemical stabilities, and proton conductivities of the S-PEEK/PHSF films were investigated. The S-PEEK/PHSF composite films were found to be homogeneous by SEM observations. Ion exchange capacities of S-PEEK, S-PEEK/PHSF 5, 10, and 20 wt.% films were 1.83, 1.95, 1.99, and 2.04 meq/g, respectively. Water uptakes and swelling ratios of the composite films decreased with increasing of PHSF contents. These results suggested that interactions between PHSF and S-PEEK depressed water adsorption and swelling of the composite films in water. Fenton tests were carried out for the composite films in order to investigate radical durability. It was revealed that the radical durability of the films was improved by adding the PHSF. S-PEEK/PHSF 5 and 10 wt.% films showed the proton conductivity of 2.82 × 10-2 and 2.93 × 10-2 S/cm at 80 °C and 90 %RH, which was higher than that of S-PEEK films.

Polythiophene derivatives show interesting optical and electrical properties. Especially, optically active polythiophene derivatives have attracted much attention because of their unique structures and organization. These properties are greatly dependent on the degree of regioregularity, which can be defined as the percentage of head-to-tail couplings. High regioregularity leads to less steric hindrance and longer π-conjugation. In this study, poly(3-[2-((S)-l-methyloctyloxy)ethyl]thiophene) (P(S)MOET), which has an optically active substituent at the 3-position of the thiophene ring, was synthesized according to the Rieke method. Obtained P(S)MOET had two fractions of high molecular weight (Mw = 44,500) and low molecular weight (Mw = 26,500). The head-to-tail ratio of high Mw P(S)MOET measured by 1H NMR was 95 %. Multi-layer EL device was fabricated with the configuration of an ITO/PEDOT:PSS/P(S)MOET/Alq3/Al-Li. The EL device emitted orange light with the maximum brightness of 60 cd m-2.

Alternating copolymer of chiral thiophene and non-substituted thiophene, poly(3-[2-((S)-(+)-lmethyloctyloxy)ethyl]-2,2'-bithiophene) (P(S)MOET-T), and regioregular chiral polythiophene, head-to-tail poly(3-[2-((S)-(+)-l- methyloctyloxy)ethyl]thiophene) (HT-P(S)MOET), were synthesized by Rieke method. The molecular weight of P(S)MOET-T was Mn = 17,800, Mw = 28,500, and Mw/Mn = 1.60, and that of HT-P(S)MOE1 was Mn = 28,300, Mw = 38,300, and Mw/Mn =1.35. The head-to-tail ratios of P(S)MOET-T and HT-P(S)MOET were estimated to be 95 % by 1H NMR spectroscopy. Optical properities of P(S)MOET-T and HT-P(S)MOET were measured by UV-Vis and fluorescence spectroscopy. A maximum absorption of P(S)MOET-T in the solid state was observed at 541 nm, which is 14 nm longer than that of /f7VP(S)MOET. A fluorescence maximum of P(S)MOET-T was 129 nm shorter than that of HT-P(S)MOET. These results suggest that the ring planarity of P(S)MOET-T is higher than that of HT-P(S)MOET.

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.

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.

In polyacetylene and polydiacetylene oligomers, photoluminescence (PL) is induced from the dipole-forbidden state by vibronic coupling. The assumption that the PL in polythiophene (PT) and poly(p-phenylene vinylene) (PPV) also includes this induced component, consistently explains many experimental results. In this work, we focus on the temperature dependence of the time-integrated and time-resolved PL spectra of a PT derivative and unsubstituted PPV, and demonstrate the validity of the above model for their temperature dependence. Applying this model to the hitherto unresolved drastic PL spectral change of unsubstituted PPV, we propose that the spectral change and the spectral shape itself can be understood as resulting from a contribution to the PL from the 2A(g) state coupled with a change in the ordering of the 2A(g) and the 1B(u) states at low temperatures.

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.

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.

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 ° 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 ° C. This value was usually maintained up to 160 ° 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. © 2004 Elsevier B.V. All rights reserved.

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

Direct methanol fuel cells (DMFCs) are promising candidates for portable power sources and electric vehicle applications due to advantage of the simple system design. In this study, the preparation of complexes of sulfonated poly(4-phenoxybenzoyl-l,4-phenylene) (S-PPBP) and polymer electrolytes with phosphoric acid groups (PPHP) were attemped in order to obtain polymer electrode membrane with low methanol permeability. DMFC performance of S-PPBP/PPHP was measured at 60°C under ambient pressure by using 1 M methanol aq. and air. The membrane electrode assembly consisting of a S-PPBP/PPHP membrane and Nafion® binder showed maximum power density of about 86 mW/cm2. The OCV of the DMFC S-PPBP/PPHP DMFC (0.772 V) was higher than that of Nafion® DMFC (0.603 V), because the methanol permeability of S-PPBP/PPHP membranes was lower than that of Nafion® membranes.

Polycarbonate (PC) is one of super engineering plastics because of their good transparency and impact-resistance. Although the surface hardness of PC is insufficient for optical and practical applications, poly(benzoyl-1,4-phenylene) (PBP) has good mechanical properties and surface hardness. In this study, the composite films were fabricated from PC and PBP with various contents, and their surface hardness was investigated. The PC/PBP blend films were fabricated by solvent casting and compression-molding methods. In scanning electron microscope (SEM) images of the obtained PC/PBP blend films, phase separation was not observed. From dynamic mechanical spectroscopy measurements, all PC/PBP blend films showed a single glass transition temperature. The surface hardness of PC/PBP blend films was estimated by optical transmittance from 500 nm to 700 nm before and after abrasion using a coating tester with steel wool. These results of hardness tests showed that the surface hardness of PC/PBP blend films increased with increasing PBP content. In addition, the compression-molded films had the good adhesion between PC and PBP, and the surface hardness of films was comparable to PBP.

Polymer light-emitting diodes (PLEDs) have attracted attention for their potential application in flat-panel displays and wide area light sources. π-Conjugated polymers have been studied as the emitting layer of PLEDs. Among π-conjugated polymers, polythiophene derivatives have been found to show interesting and unique properties such as good processability, solubility, and optical properties which are strongly influenced by their morphology and molecular organization. In this study, to investigate the effect of functional groups of polythiophene on their electroluminescence properties, polythiophene derivatives which have various side chains (heteroaromatic (poly(3- (benzothiazol-2-yl)thiophene) PBTT), chiral (poly(3-[2-(1-methyloctyloxy)ethyl] thiophene) P(S)MOET), and alkyl (poly(3-hexylthiophene) PHT)) were synthesized by oxidative polymerization. The polymers were characterized by 1H-NMR spectra, elemental analysis, and GPC measurement. The Head-to-Tail ratios of polymers were estimated to be about 70% by 1H-NMR spectra. The absorption and fluorescence peaks were dependent on functional groups.