Transactions of the Materials Research Society of Japan
Online ISSN : 2188-1650
Print ISSN : 1382-3469
ISSN-L : 1382-3469
33 巻, 1 号
選択された号の論文の44件中1~44を表示しています
  • Hironobu Abiko
    2008 年 33 巻 1 号 p. 1-8
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Template materials, carbon ingredients and their impregnation state into templates are important factors for synthesis of new porous carbon materials by template method. The synthesis conditions are assumed to have marked influence on pore development of the specimens. Particularly, pore volume in microporous and mesoporous region, specific surface area and yield point or yield constant of the specimens are extremely interested for practical application of the materials. In this research, several porous carbon specimens have been prepared under different conditions by the use of several kinds of natural soils or clays for templates, and we have investigated effects by the above conditions; filling period of ingredient for carbon, fill pressure, carbonization temperature, and so on. Qualitative difference of template materials has been also examined from viewpoints of synthesis procedures.
  • Jun Kawakami, Rie Ohtake, Ryo Miyamoto, Masahiko Nagaki, Shunji Ito
    2008 年 33 巻 1 号 p. 9-11
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    2-(Benzo-d-thiazol-2-yl)quinoline (BTQ) was synthesized and tested for its use as a fluorescent chemosensor material for Hg2+. We investigated the metal-ion recognition of BTQ by adding several metal ions (M2+) to a solution of BTQ in acetonitrile. The shape and intensity of the fluorescence spectra with excitation at 350 nm did not change upon addition of Cd2+, Ni2+, Zn2+, Co2+, Ca2+, and Ba2+ . However, the fluorescence emission of BTQ was quenched with the addition of Hg2+ or Cu2+. Furthermore, when excitation at 373 nm was used, fluorescence was not detected for pure BTQ and BTQ with Cd2+ , Ni2+ , Zn2+ , Co2+ , Ca2+ , Ba2+ , or Cu2+ in acetonitrile solution, whereas fluorescence was detected for BTQ in the presence of Hg2+. Thus, BTQ is well suited for use as a fluorescent chemosensor material for Hg2+.
  • Yasuhiro Yoneda, Naohiko Yasuda
    2008 年 33 巻 1 号 p. 15-18
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Pb Lm-edge absorption spectra of ordered and disordered Pb(In0.5Nb0.5)O3 (PIN) were analyzed. The absorption edges of both the ordered and disordered PIN were shifted depending on the thermal condition of post-annealing. A clear edge shift was observed between the ordered and disordered PIN crystals. The local environments of the Pb atoms were different in these PIN crystals. The edge shift can be interpreted by introducing disarrangement of B-site atoms. Disordering of B-site atoms did not influence the environment of B-site atoms though was in Pb environment.
  • Yuuki Kitanaka, Yuji Noguchi, Masaru Miyayama
    2008 年 33 巻 1 号 p. 19-22
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We have investigated the domain structures and their dynamics induced by electric field along the c axis in ferroelectric Bi4Ti3O12 single crystals, taking into account the two spontaneous polarization (Ps) components along the a (Ps(a)) and c axes (Ps(c)). Piezoresponse force microscope observations showed that 90° domain walls (composed of the Ps(a) component) clamp the motion of Ps(c) domain walls, leading to a lower remanent polarization along the c axis. Annealing the crystals under oxidation atmosphere led to not only a complete Ps(c) switching without clamped Ps(c) domains, but also a marked increase in the coercive field for the Ps(c) switching (Ec(c)). The behavior of Ec(c), which cannot be explained by the domain wall pinning attributed to oxygen vacancies, was tentatively interpreted as a result of the interaction between the domain walls composed of Ps(c) and electron hole induced by the oxidation treatment.
  • Hironori Fujisawa, Masayoshi Kume, Masaru Shimizu
    2008 年 33 巻 1 号 p. 23-26
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We investigated epitaxial growth of PbTiO3 thin films on coherent and incoherent Pt thin films on SrTiO3(100) by metal organic chemical vapor deposition and their ferroelectric properties. PbTiO3 films were grown on both Pt films in the Volmer-Weber mode. The coalescence of neighboring islands observed at the earlier growth stage on coherent Pt films than on incoherent Pt films due to the higher crystalline orientation and smoother surface. Therefore, the minimum thickness above which continuous PbTiO3 films were formed on coherent Pt films, 50nm, was smaller than 100nm on incoherent Pt films. 50nm-thick PbTiO3 films on coherent Pt films showed D-E hysteresis loops with a remanent polarization of 64.0C/cm2 and a coercive field of 275kV/cm.
  • S. Kitagawa, Y. Horibe, K. Yoshii, M. Suzuki, Y. Noguchi, S. Nishihara ...
    2008 年 33 巻 1 号 p. 27-30
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Microstructures related to the ferroelectric (FE) properties in (1-x)BiFeO3-xBaTiO3 were examined mainly by a transmission electron microscopy, in combination with conventional magnetic and dielectric measurements. It was found that macroscopic-sized FE domain structures in BiFeO3 changed into fine FE microstructures with the 20-30nm size in the x=0.25 compound, as the BaTiO3 concentration (x) was increased. In addition, we found characteristic tweed-like contrast due to the strain field in the x=0.33 compound at room temperature. We carefully investigated a spatial distribution of the FE microdomains in the x=0.25 compound by obtaining real-space images and determined the spatial configuration of the spontaneous polarization in each FE microdomains.
  • Y. Matsuo, Y. Horibe, K. Yoshii, N. Ikeda, S. Mori
    2008 年 33 巻 1 号 p. 31-34
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We investigated magnetic/dielectric properties and related microstructures in LuFeCuO4, which was obtained by substituting Cu2+ for Fe2+ in LuFe2O4. It was found that LuFeCuO4 shows a characteristic low-frequency dielectric dispersion around 300K. We analyzed it using the Debye model and found that LuFeCuO4 is a dielectric compound with an orientational polarization. Electron diffraction experiments revealed that there exists characteristic zigzag-shaped diffuse scattering in LuFeCuO4. In addition, we found the presence of nano-sized domains, which consist of a short-range ordering of Fe3+ and Cu2+ on the triangular lattice. The present results suggest that the short-range ordering gives rise to some anomalous dielectric properties in LuFeCuO4.
  • Yuya Ito, Makoto Moriya, Wataru Sakamoto, Toshinobu Yogo
    2008 年 33 巻 1 号 p. 35-38
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Ferroelectric 0.7BiFeO3-0.3BaTiO3 and 0.7BiFe0.95Mn0.05O3-0.3BaTi03 thin films have been prepared by the chemical solution deposition. Perovskite single-phase thin films with homogeneous surface morphology were successfully fabricated at 700°C on Pt/TiOx/SiO2/Si substrates. Although typical polarization (F)-electric field (E) hysteresis loops were observed for 0.7BiFeO3-0.3BaTiO3 thin films, their insulation resistance was relatively low at room temperature. Mn doping for Fe site of the 0.7BiFeO3-0.3BaTiO3 was very effective in improving the leakage current property at high applied fields and the surface morphology of the resultant thin films. 5 mol% Mn-doped films exhibited larger ferroelectricity at room temperature. Furthermore, at a low temperature of -190°C, the remanent polarization (Pr) of the 700°C-prepared 0.7BiFeO3-0.3BaTiO3 and 0.7BiFe0.95Mn0.05O3-0.3BaTiO3 thin films were approximately 30 and 46 C/cm2, respectively.
  • Muneyasu Suzuki, Tetsuo Uchikoshi, Yuji Noguchi, Masaru Miyayama
    2008 年 33 巻 1 号 p. 39-41
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Magnetic-field-assisted electrophoretic deposition (B-assisted EPD) method has been applied for synthesizing a(b)-axis-oriented Bi5FeTi3O15 ceramics, and the effects of the B-assisted EPD on grain orientation and microstructures have been investigated. The sintering at 1100 C of the green compact obtained by the B-assisted EPD led to dense ceramics with a high relative sintered density of 98 %. X-ray diffraction analysis shows that the a(b)-axis-orientation degree of the grain oriented ceramics evaluated by the Lotgering method was 45 %.
  • M. Ikezaki, Y. Noguchi, K. Katayama, M. Miyayama
    2008 年 33 巻 1 号 p. 43-46
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Super lattice-structured Bi4Ti3O12- PbBi4Ti4O15 single crystals were grown, and the effects of oxidation and reduction of the polarization hysteresis and leakage current along the a axis were investigated at room temperature. High PO2 annealing gave rise to an increase in leakage current, while annealing in N2 atmosphere yielded a marked decrease in leakage current. These results show that electron hole is the dominant carrier for the leakage current. A well-saturated polarization hysteresis with a remanent polarization of 41 C/cm2 was observed for air-annealed crystals, which is suggested to originate from the peculiar ferroelectric displacement of Bi in the Bi2O2 layers.
  • Yoshihiro Terado, Chikako Moriyoshi, Yoshihiro Kuroiwa, Yasuhisa Yama ...
    2008 年 33 巻 1 号 p. 47-51
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    High-energy synchrotron-radiation powder-diffraction experiments for PbZr1-xTixO3 (PZT: 0≦x≦1) and (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-PT: 0≦x≦0.3) have been performed to investigate the relationship between the structural features of the cubic phase at high temperatures and the morphotropic phase boundary (MPB) at low temperatures. Our precise Rietveld analyses for PZT and PZN-PT with various compositions have revealed that the Pb atom in the cubic phase is disordered around the cubic corner site, and the thermal motions abruptly change at the distinctive composition x ~ 0.5 for PZT and at x ~ 0.15 for PZN-PT, where MPB of each solid solution separates the tetragonal and rhombohedral phases at low temperatures. No anomalous change in thermal motions is detected for other atoms. Hence, we consider that the appearance of MPB is strongly related to the change in local environment around the Pb atom.
  • Katsuya Yamamoto, Yuuki Kitanaka, Muneyasu Suzuki, Yuji Noguchi, Masar ...
    2008 年 33 巻 1 号 p. 53-56
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We have investigated the effects of high-oxygen-pressure crystal growth of ferroelectric Bi4Ti3O12 on the polarization properties along the a(b) axis. Domain observations by piezoresponse force microscope demonstrated that a small remanent polarization (Pr) for the crystals grown with 0.02 MPa oxygen pressure is attributed to the clamping of 90° domain walls by oxygen vacancies. The vacancy formation of Bi and 0 during crystal growth at high temperatures is suppressed at a higher oxygen pressure, leading to a larger Pr of 47 C/cm2 for the crystals grown at I MPa oxygen. High-oxygen-pressure sintering is proposed to be effective for obtaining Bi4Ti3O12-based devices with enhanced polarization properties.
  • Satoshi Wada, Koutaro Takeda, Takaaki Tsurumi, Toshio Kimura
    2008 年 33 巻 1 号 p. 57-60
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Lead-free ferroelectrics have become highly attractive materials from the viewpoint of a solution to environmental problems. However, as compared with Pb(Zr,Ti)O3 (PZT) ceramics, their ferroelectric related properties were poor, and it is difficult to replace the PZT ceramics. To achieve much higher piezoelectric properties than those of PZT ceramics, the domain average engineering i.e., engineered domain configuration, is an important technique, and should be applied to lead-free ferroelectric materials. Barium titanate (BaTiO3) crystal is typical lead-free ferroelectrics and there have been a number of reports on its domain average engineering. Recently, for the tetragonal BaTiO3 crystals with the engineered domain configurations, it was found that the piezoelectric properties were significantly improved with increasing domain wall densities. This result suggests a possibility that the domain walls in the engineered domain configuration could contribute to the piezoelectric properties. Thus, to explain the domain wall contribution to the piezoelectric properties, the piezoelectric properties of the BaTiO3 crystals were investigated as a function of domain size. Moreover, this concept was applied to grain oriented BaTiO3 ceramics, and finally the lead-free piezoelectrics with d33 of 800 pC/N were prepared by domain wall engineering.
  • Takashi Nishida, Takashi Nozaka, Masahiro Echizen, Hiroaki Takeda, Kiy ...
    2008 年 33 巻 1 号 p. 61-64
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Pb(Zr,Ti)O3 (PZT) thin film capacitors have been widely investigated, due to their various applications, including ferroelectric memories and micro-electromechanical systems. However, degradation of electrical properties of the films is caused by crystal defects, and the exact mechanism for this has not been fully elucidated. We have attempted to investigate defects in the films by thermally stimulated current (TSC) measurements, and the identification of the observed TSC peaks and the relationships between the degradation and TSC signal. However, the behavior of carriers in the films, such as recombination, has not been fully elucidated, and quantitative evaluation of carrier movement and defect density has been difficult. We have therefore investigated the influence of UV-light irradiation on electrical properties of PZT film capacitors. The leakage current and capacitance measurements under UV light (= 250 nm) irradiation were carried out. The current and capacitance were gradually changed by the irradiation, revealing that the relaxation time and lifetime of carriers in the films were sufficiently high, above 100 s, and the decrease in the observed current in TSC by recombination seems to be small. The relaxation time slightly decreased with increasing temperature and applied voltage because of carrier drift. The drift properties were also discussed.
  • Takashi Nozaka, Takashi Nishida, Yoji Mizutani, Bhakdisongkhram Gun, T ...
    2008 年 33 巻 1 号 p. 65-68
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    In this study, we investigated the crystal structure of polycrystalline BST films deposited on the glazed-Al203 and -Al203 substrates and its electrical properties. The BST films were prepared on the Pt bottom electrode/substrates by the chemical solution deposition (CSD) method. The BST films annealed at 800°C using rapid thermal annealing (RTA) were grown in random orientation on each substrate. The grain sizes were 80 nm and the average surface roughnesses Ra were approximately 3.0 nm. The dielectric constant, tan and tunability (at 428 kV/cm) of the Pt/BST/Pt/-Al2O3 film were 476, 0.0321 and 68.6% respectively, and the Pt/BST/Pt/glazed-Al2O3 film also showed practical figures, 429, 0.0498 and 58.3% respectively. We confirmed that the tunability of the Pt/BST/Pt/glazed-Al2O3 film can be maintained at above 50% up to an environmental temperature of around 80°C. This suggests that high quality BST films to apply on tunable microwave devices can be formed on a very inexpensive glazed-Al2O3 substrate.
  • Koichi Kubo, Masahiro Echizen, Takashi Nishida, Hiroaki Takeda, Kiyosh ...
    2008 年 33 巻 1 号 p. 69-72
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    PbTiO3 (PTO) ferroelectric nanocrystals were deposited on atomically flat α-Al2O3 (0001) substrates by RF magnetron sputtering. The atomically flat α-Al2O3 (0001) substrates were obtained by annealing the α-Al2O3 (0001) substrate for about 3 hours at 1000-1200°C and the surface with atomic steps and terrace was observed by atomic force microscopy (AFM). In the RF magnetron sputtering method, high energy particles were sputtered on the substrates. Therefore, nucleation of crystals is stimulated at the atomic steps by control particles sputtered with high energy. Their particles were controlled by setting a cover material (α-Al2O3) on the substrates. Judging from the result of observations with XRD, XRF and AFM, the crystallized PTO nanocrystals were triangular in shape, with side length of 100-150nm and height of 20-30nm. In addition, it was confirmed by AFM that, when the cover allowed sputtered particles to approach ascending atomic steps, PTO nanocrystals fell into alignment along the atomic steps. So, it was found that relation between direction of steps and direction in which sputtered particles came flying were very important.
  • Atsuhiro Fujimori, Hiroko Hoshizawa, Ryoko Kobayashi, Natsuki Sato
    2008 年 33 巻 1 号 p. 75-78
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Orientation for functional carbazole groups in comb copolymers were controlled using co-polymerization with long-chain vinyl compounds and the method of organized molecular films. Their structures were estimated using in-plane X-ray diffraction (XRD) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. In the bulk state, fluorinated comb copolymers form side-chain crystal at a two-dimensional lattice spacing of 5.0 A. From the in-plane XRD measurements of multilayers on solids, the two-dimensional lattice structures of fluorinated comb copolymer films containing NVCz units were different from those in their bulk states. Polarized NEXAFS measurements showed highly ordered orientation of carbazole groups in the films. This well-ordered arrangement of functional groups should be caused by the  interaction between the carbazole rings.
  • Satoshi Kobayashi, Syohei Jindo, Hiroko Hoshizawa, Atsuhiro Fujirnori
    2008 年 33 巻 1 号 p. 79-82
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    The fine structures in the solid state and molecular orientation in Langmuir-Blodgett films of newly synthesized ternary comb copolymers with N-vinylcarbazole were investigated by wide-angle X-ray diffraction (XRD), small angle X-ray scattering, in-plane XRD, out-of plane XRD and atomic force microscopy. From the results of XRD in bulk, two kinds of short spacing peaks based on the formation of the sub-cell for fluorinated and hydrogenated side-chains were confirmed. Further, these ternary copolymers formed highly ordered layer structure. In addition, these ternary copolymers formed extremely condensed monolayers on the water surface. From the out-of plane XRD measurements of multilayers, formation of highly ordered layer structure was conformed. From the results of in-plane XRD and AFM, it was found that phase-separated structures between fluorinated and hydrogenated side-chains could not form in two-dimensional films. These structural changes may be cause by the  interaction between the carbazole rings.
  • Yuichiro Hayasaka, Atsuhiro Fujimori
    2008 年 33 巻 1 号 p. 83-86
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Changes in fine structure with drawing of poly[tetrafluoroethylene-co-(perfluoroethylvinylether)] (abbrev. PFA) transparent thin films and fibers were investigated by wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS) methods. The PFA is random copolymer containing comonomer units of fluorinated ether derivatives as the side-chain in the repeating tetrafluoroethylene backbone. This polymer is crystallized as lamella crystal in their thin films and fibers although polytetrafluoroethylene itself usually forms extended-chain crystals because of their inflexible and rigid nature of 13/6 helices. PFA are exhibited thicker lamella thickness at least 30 nm by the SAXS measurement than general hydrogenated crystalline polymer. In these copolymers, we consider the formation of 'switchboard-type' lamellae model according to P. J. Flory's suggestion. With increase in elongation to their thin film, the four points SAXS diagrams has developed in the photograph of PF A transparent films, which means that a particular kind of layer structure is formed, alternately tilted lamella arrangements as a 'Herring-bone'.
  • Natsuki Sato, Ryoko Kobayashi, Atsuhiro Fujimori
    2008 年 33 巻 1 号 p. 87-90
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Structures in the solid state and in the organized molecular films of comb copolymers containing 2-vinyl-4, 6-diamino-s-triazine (VDAT) were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and surface pressure-area (-A) isotherm measurements. The comb copolymers used in this study were synthesized by co-polymerization of fluorinated or hydrogenated long-chain vinyl compounds and VDAT with AIBN initiator in acetone solution. From the results of XRD and DSC, these copolymers formed side-chain crystals in the bulk states. Fluorinated comb copolymers had a short spacing of 5.0 A for the two-dimensional side-chain lattice whereas hydrogenated polymers formed sub-cell structure at a lattice spacing of 4.2 A. These comb copolymers formed stable condensed monolayers on the water surface estimated by -A isotherms. The molecular arrangement of Langmuir-Blodgett film of comb copolymers corresponded well to that of bulk state from the results of in-plane XRD measurements.
  • Yoshitaka Takahara, Naoya Ninorniya, Atsuhiro Fujirnori
    2008 年 33 巻 1 号 p. 91-94
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Langmuir-Blodgett (LB) films of organo-modified montmorillonite (abbreviated as C18-clay) and poly(L-lactic acid) (PLLA) / C18-clay intercalated multilayer films formed and the structures were investigated by out-of plane X-ray diffraction (XRD), in-plane XRD, and atomic force microscopy (AFM). Intercalated multilayers were constructed by the application of the LB method to C18-clay monolayers and the horizontal lifting method to PLLA monolayers. Further, surface morphology of PLLA : C18-clay mixed Z-type monolayers on solid were also estimated by AFM. Because these systems are two-dimensional ultrathin layer models related to polymer / clay nanocomposite as hybrid material in bulk, experimental results in this study are discussed in the view of formation mechanism and origin of functionality of three-dimensional polymer / clay nanocomposite materials, referring to the structural information of these organized molecular films.
  • Yuki Koyano, Yuichi Sugano, Hiroko Moshino, Yasuhiro F. Miura, Michio ...
    2008 年 33 巻 1 号 p. 95-98
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We report the restoration of J-band in the merocyanine (MS)-containing LB films induced by the repeated application of heat treatments; a dry-heat treatment (DHT) followed by hydrothermal treatments under 100% humidity (HTTs) (i.e., DHT - NxHTT) together with the dissociation of the as-deposited J-band induced by DHTs. The law of additivity is found to roughly hold among the total heating in the NxDHT process, during which a fraction of MS molecules is subjected to degradation. In the process of DHT - NxHTT, the J-band component, once totally dissociated by DHT, is restored by NxHTT. The occurrence and growth of the restored J-band, and the change in film texture are found to be identifiable with those seen in the second-stage when HTT is directly applied to the as-deposited film. It is shown that HTT is feasible as another means to restore the J-band in the DHT-induced red films with lesser risk of degradation than the so far known basic treatments (ATs) in vapor and liquid phases that may be associated with unfavorable chemical reactions.
  • Yasuhiro Nishimura, Takaaki Manaka, Mitsumasa Iwamoto
    2008 年 33 巻 1 号 p. 99-102
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Bio-mimetic membrane, hybrid bilayer membrane (HBM), was prepared on solid substrate using Self-Assemly and Vesicle Fusion (VF) methods. The HBM films were composed of self-assembled monolayer (SAM) of alkanthiol and phosphatidylcholine. Micro-patterned composite membranes of lipids were made on solid substrate with micro-patterned SAM by a micro-contact printing (CP) method. AFM and Kelvin probe force microscopy (KFM) observation was conducted under height and phase modes, and surface potential, respectively. The height imaging showed that the flat surface was formed by the CP method. Furthermore, the phase imaging and surface potential imaging revealed the micro-pattern formation. These results show that an artificial bilayer was successfully prepared on the surface without SAM, and lipid monolayer on the surface with SAM. These results were supported by the cyclic-voltammetry (CV) and surface potential.
  • Hiroko Moshino, Yuki Koyano, Yuichi Sugano, Yasuhiro F. Miura , Michio ...
    2008 年 33 巻 1 号 p. 103-106
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Hydrothermal and dry-heat treatments (HTT and DHT, respectively) are studied on the mixed LB films of a merocyanine and Cd arachidate. The HTT process under 100%-humidity condition is found to involve two stages: the as-deposited J-band first dissociates and then a new phase of J-band appears to grow associated with round-shaped superstructure as large as up to ~0.1 mm in diameter. The DHT process under dry ambient dissociates the original J-band without appreciable changes in film texture. The first stage of HTT terminates within 1 min at temperatures higher than 60°C, while the J-band peak after DHT at 60°C for 30 min retains ea. 85% of its original height. X-ray diffraction reveals that the LB lamellar structure remains intact in both HTT and DHT processes with an enhanced ordering of Cd ion alignment. As for the role of the water content, the lubrication effect is preferred to the hydration effect.
  • Yuichi Sugano, Yuki Koyano, Hiroko Moshino, Yasuhiro F. Miura, Michio ...
    2008 年 33 巻 1 号 p. 107-110
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We have examined the thermal stability of the reorganized J-band induced by the hydrothermal treatment under 100% humidity (HTT) in merocyanine-arachidic acid (MS-C20) mixed Langmuir-Blodgett (LB) films. The reorganized J-band is found to be more stable than the as-deposited J-band: the former remains almost unchanged after DHT at 70C for 75 min in total, and retains 86% of the initial height after dry-heat treatment (DHT) at 90C for 270 min in total, while the latter loses 70% of the initial height after DHT at 90C for 40 min in total. The reorganized J-band is dissociated by DHT at ll0C for 150 min, resulting in a spectrum considerably different from those observed after DHT at tH 90C. The observed thermal behavior is suggested to be closely related to that of the LB lamellar structure in CdC20 LB films stabilized by Cd2+ ions.
  • Masahiro Sato, Hirobumi Shibata, Hideki Sakai, Masahiko Abe, Mutsuyosh ...
    2008 年 33 巻 1 号 p. 111-114
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We demonstrated a new method for directed self-assembly of zirconia thin films, reflecting the phase-separated structures of mixed Langmuir-Blodgett (LB) films, through a sol-gel route. Templates were fabricated by heat treatment of mixed LB films of fatty acid and silane-coupling agent, followed by selective removal of the fatty acid. Templates functionalized with amino groups were immersed into zirconia precursor solution. Atomic force microscopy and Kelvin probe force microscopy images showed that the films prepared under optimal conditions had products with the same surface potential within the ex-domain region. Energy dispersive X-ray (EDX) spectra of the products in the ex-domain region clearly showed a peak assigned to Zr. These results confirmed that the patterned zirconia films were prepared on the templates fabricated from phase-separated LB films.
  • Takehito Tomioka, Hirobumi Hirobumi Shibata, Mutsuyoshi Matsumoto
    2008 年 33 巻 1 号 p. 115-118
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We studied the effect of fabrication conditions on the structures and photoreactions of Langmuir and Langmuir-Blodgett (LB) films of an amphiphilic derivative of spiropyran (SP1822). Pure LB films of SP1822 and mixed LB films of SP1822 and arachidic acid (C20) fabricated at high fabrication temperatures consisted of circular domains with a constant height of 4 nm. UV illumination gave rise to the formation of J-aggregates, accompanied by the development of structures extending radially from the nuclei in the domains. Pure LB films of SP 1822 fabricated at low temperatures were comprised of 4-nm-high domains with a considerable amount of voids. On UV illumination, J-aggregation proceeded accompanied with morphological changes. In the mixed LB films of SP1822 and C20 fabricated at low temperatures, the presence of C20 molecules suppressed the diffusion of dye molecules in the films, thereby inhibiting the J-aggregation.
  • Kenji Hisada, Akiko Hino, Saori Inoue, Teruo Hori
    2008 年 33 巻 1 号 p. 119-122
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We have investigated the frictional properties of the Langmuir-Blodgett (LB) films by lateral force microscope. The LB films were prepared with the amphiphiles having fluorocarbon or hydrocarbon tails. The frictional behavior was discussed as a function of the terminal atom of hydrophobic end and the size of the hydrophilic groups. The films prepared with F-terminated amphiphiles showed friction force lower than those prepared with corresponding H-terminated amphiphiles. The mono layers of the fluorinated diols gave higher friction at lower normal load. When the normal load was less than 10 nN, large hydrophilic head of diol increases the free volume around the hydrophobic chain. The large free volume accelerates energy dissipation within the monolayer, which enlarges the friction at lower load.
  • Keiichi Ikegami, Yoko Tatewaki
    2008 年 33 巻 1 号 p. 123-126
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    To investigate the so-called monomer shifts in aggregates of merocyanine dyes that bear a donor-acceptor type chromophore, a simple model has been introduced to describe the electronic structure of such a chromophore. This model can be solved analytically and the obtained solution tells us that the physical quantities relating to the optical properties of the system, i.e., the excitation energy, the transition dipole moment, the static dipole moment at the ground state, and the static dipole moment at the excited state strongly depend on the extent of the bond alternation in the chromophore, which includes seven atomic Pz orbitals. Based on this model, as a consequence, possibility of anomalous monomer shifts in the merocyanine J-aggregates has been demonstrated.
  • Yasuhiro Akita, Tomohito Ide, Atsunori Mori, Kazuaki Kudo, Shigeru Mac ...
    2008 年 33 巻 1 号 p. 127-130
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Pi-Conjugated bithiophene derivatives are expected to show remarkable optical and electrochemical properties owing to the characteristic electronic state. Recently, we reported that Pd-catalyzed C-H homocoupling of thiophene derivatives smoothly occurred in the presence of AgN03 and KF, and the corresponding bithiophene derivatives were obtained in high yields. In this study, the re-conjugated bithiophene derivatives having aryl groups symmetrically through carbon-carbon double bonds were synthesized by the C-H homocoupling reaction and Wittig reaction. In order to clarify the influence of terminal functional groups to physical properties, energy gaps were estimated from the onset of absorption in the UV -vis spectrum and quantum yields of fluorescence were calculated on the basis of fluorescence spectra. Furthermore, standard oxidation potentials were determined by cyclic voltammetry and the electron properties were calculated by density functional theory method.
  • Fumihiko Matsuyama, Kazuo Nishitani, Teppei Maeda, Tomoyasu Oda, Nobuy ...
    2008 年 33 巻 1 号 p. 131-134
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Little and/or Ginzburg proposed low dimensional transport systems as an excitonic model to obtain a room temperature superconductivity. We have studied electrical conducting properties observed in self-assembly monolayers of C60-O-C8SH derivatives (C60-SAM) (as a dielectric layer) on Au ultrathin films (as a conductive layer) to realize the Ginzburg's excitonic superconducting model. Electrode Au films were prepared on flat MgO(l00) substrates trough the metal mask by sputtering, and then sputtered Au atoms passed around behind the holes of the mask. Au ultrathin films were successively deposited without the mask by sputtering. The An-deposited specimens were soaked in a 0.01 mM benzene solution of C60 derivatives for 20 h at room temperature to form C60-SAM. Several specimens revealed the deviation from linear temperature dependence of resistance accompanying with steep decrease of resistivity in the temperature region less than 100 K - 130 K. Such the resistivity anomaly was observed only in the specimens which had ultrathin Au film area with the dimension of less than about 10 m.
  • Yuichiro Hayasaka, Tadashi Tamura, Atsuhiro Fujimori
    2008 年 33 巻 1 号 p. 137-140
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Fine structure in the matrix polymer and dispersion state of fillers for poly [tetrafluoroethylene-co-(perfluoroalkylvinylether)] (abbrev. PFA) I nano-fillers (such as organo-modified smectite, organo-modified mica, and porous silica particles) composites were investigated by wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). From the results of TEM observation, it was found that nano-fillers were almost uniformly dispersed in PF A matrix. Further, PFA I nano-filler composites are exhibited relatively larger distance between lamellar gravity at least 30 nm estimated by SAXS than general hydrogenated crystalline polymer. This result means that fluorinated copolymer formed the thicker lamella crystal. In addition, a melting peak these nanocomposites showed in DSC thermograms was shifted to higher temperature side than that of neat PF A. It is suggested that the origin of this thermal behavior corresponds to occurrence the nucleator effect of nano-fillers to the matrix PFA.
  • Nobuyuki Ishikura, Minoru Fujii, Masaki Inui, Shinji Hayashi
    2008 年 33 巻 1 号 p. 141-144
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We studied metal-enhanced photoluminescence (PL) from Si nanocrystals (Si-ncs) placed near rough Au films. Au films with different degree of roughness were prepared by electroless Au plating. We found that the PL intensity and the decay rate increase as the roughness becomes large. The PL excitation spectra revealed that the PL enhancement is the largest when the excitation wavelength corresponds to that of the surface plasmon resonance of rough Au films. The result combined with the emission wavelength dependence of PL enhancement factors suggest that the PL enhancement is caused by the enhancement of an electric field of incident light due to the excitation of surface plasmons supported by the rough Au films and also the increase of radiative decay rate of Si-ncs.
  • Hideki Nabika, Baku Takimoto, Kei Murakoshi
    2008 年 33 巻 1 号 p. 145-148
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We investigated the lipid bilayer self-spreading behavior on glass substrates modified with complex array of nano-architectures. Simple way of constructing a binary array of metallic / organic nano-architectures was established. The metallic nano-architecture was prepared by nano-sphere lithography (NSL) method. By controlling the drying process in NSL, periodic array of donut-shaped organic nano-architectures, 200 nm in diameter and 4 nm in height, was also constructed on the substrate. In the presence of metallic nano-architectures, the self-spreading velocity was significantly reduced due to the energy cost imposed on passing through the nano-architectures. The self-spreading phenomenon was found to be intact even on the metallic / organic binary array substrate. Fluorescence microscope revealed that the organic nano-architectures kept their initial structures during the self-spreading around the architectures.
  • Yumi Kuboshima, Kazuya Yamamoto, Takao Aoyagi
    2008 年 33 巻 1 号 p. 149-152
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We have studied the preparations and characterizations of nano-sized complexes derived from stimuli-responsive AB- or ABA-type block copolymers and G3 poly(amidoamine) dendrimers. The block copolymers consisted of thermo-responsive poly(N-isopropylacrylamide) and poly(methacrylic acid), respectively. The nano-sized complexes were consequent on the electrostatic interactions between carboxyl groups of the block copolymers and amino groups of dendrimers in aqueous solutions. We confirmed the effective nano-sized complex formation by dynamic light scattering measurement and transmission electron microscope. Interestingly, the nano-sized complex derived from ABA-type triblock copolymer had smaller size than that from AB-type diblock copolymer. The condensation reactions between the block copolymers and the dendrimers effectively improved the stability of the nano-sized complexes in aqueous solutions. Furthermore, we also confirmed the sensitive response in temperature change.
  • Hirokazu Oda, Tomokazu Iyoda, Masaru Nakagawa
    2008 年 33 巻 1 号 p. 153-156
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    An amorphous nickel-phosphorus (Ni-P) hollow microfiber is prepared by template-synthesis with a hydrogen-bonded fibrous supramolecular template by Pd-promoted electroless deposition. To let the Ni-P microfiber show conductivity and magnetic property in this study, we carried out thermal annealing at 500 °C under an argon atmosphere in different two ways. One is the annealing after template removal with a 1 mol dm-3 NaOH aqueous solution. Another is the annealing without template removal, which was intended to reduce fabrication procedures. As a result, an annealed Ni-P hollow microfiber showed a different saturated magnetization value of 14 emu g'1 in the former and 9 emu g'1 in the latter. To understand the phenomena, we investigated the two kinds of annealed Ni-P microfibers by transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectrometry (ICP-AES), and X-ray diffractometry (XRD). Although the powder conductivity and chemical composition were hardly affected, formation of an f.c.c. nickel phase related to the magnetic property was significantly suppressed in the latter case of annealing without template removal. It was suggested that carbonization of the supramolecular template upon annealing suppressed the formation of an f.c.c. nickel crystalline phase.
  • Takaaki Tsuruoka, Asami Fujimoto, Kensuke Akamatsu, Hidemi Nawafune
    2008 年 33 巻 1 号 p. 157-160
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    The fabrication of two-dimensional, covalent bond-mediated assembly of gold nanoparticles on glass substrates is reported herein. Highly monodispersed gold nanoparticles protected by mixed monolayers comprising of decanethiol (DT) and 11-mercapto-1-undecanol (MUO) are covalently immobilized on isocyanate-bearing layers on glass substrates through carbamate-forming reaction. Specifically, two-dimensional structures of these immobilized gold nanoparticles depend on the surface monolayer coverage of MUO molecules attached on the nanoparticles. The lower coverage allows formation of ordered two-dimensional superlattice, whereas increase in the MUO coverage induces disordered assembly and sometimes domain structures, as indicated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The reason for this can be due to a steric effect and a significant change in the hydrophobicity of protective mono layers associated with interaction between immobilized gold nanoparticles.
  • Yasuhiro Tachibana, Yasuhide Otsuka, Kazuya Umekita, Susumu Kuwabata
    2008 年 33 巻 1 号 p. 161-164
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Kinetic studies at TiO2/bithiophene/electrolyte interfaces were conducted, and their parameters to the solar cell functions were related. The solar cell based upon the bithiophene sensitised TiO2 films resulted in the maximum IPCE of approximately 25 % at 400 nm. Comparison of emission studies between the bithiophene adsorbed TiO2 and Al2O3 revealed the electron injection from the excited bithiophene into the Ti02 with the efficiency of nearly 100 %. The charge recombination between the bithiophene cation and the electron in the TiO2 appeared to be fast with a half decay time of 70 s in comparison to the ruthenium dye sensitized TiO2 film (~1 ms). The bithiophene regeneration rate with the half time of 20 s was slightly faster, clarifying the inferior photocurrent performance.
  • Hirokazu Fumon, Masato Nojiri, Minoru Fujii, Shinji Hayashi, Kensuke A ...
    2008 年 33 巻 1 号 p. 165-167
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We studied the sensitized generation of singlet oxygen by surface-modified hydrophilic porous Si. Porous Si consisting of a network of Si nanocrystals acts as an efficient photosensitizer for the generation of exited state molecular oxygen called singlet oxygen. Singlet oxygen is widely used in chemistry and biology. One of the possible applications of it is photodynamic therapy of cancer (PDT). However, as-prepared porous Si is hydrophobic and thus cannot be used as singlet oxygen photosensitizer in aqueous solution. Therefore, in this work, we modified the surface of porous Si by organic molecules (allylamine). We found that allylamine-terminated hydrophilic porous Si holds the photosensitization ability, although the efficiency of singlet oxygen generation is reduced by the modification.
  • Yoshiaki Murase, Takanobu Kitagawa, Masaki Imamura, Akinori Tanaka, Hi ...
    2008 年 33 巻 1 号 p. 169-172
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We have carried out the hard X-ray photoemission study of dendrimer-Au hybrid nanoparticles/nanoclusters supported on the highly oriented pyrolytic graphite substrates. From the detailed line-shape analysis for Au 4f core-level photoemission spectrum of dendrimer-Au hybrid nanoparticles with mean diameter of 2.6 nm, it is found that Au 4f core-level spectrum consists of three components. We attribute these components to the interior Au atoms, surface Au atoms, and surface Au atoms bonded to dendrimers. Furthermore, we have investigated the valence-band photoemission spectra. From these results, we discuss the electronic structures and interfacial properties of dendrimer-Au hybrid nanoparticles/nanoclusters.
  • Fumiaki Amano, Ryu Abe, Bunsho Ohtani
    2008 年 33 巻 1 号 p. 173-176
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Nitrogen-doped titanium(IV) oxide (NT) particles were synthesized from titanate nanosheets prepared by exfoliation of lepidocrocite-like layered titanic acid using tetrabuthylammonium hydroxide. The layered composites of nanosheets with ammonium ions intercalated in the interlayer spaces, which were prepared by treatment of the nanosheets with a solution containing ammonium ion at room temperature, were transformed to anatase crystallites of titanium(IV) oxide (TiO2) by calcination in air at 723 K. The powders exhibited a yellow color corresponding to photoabsorption in the visible region (400-500 nm) presumably due to generation of a localized dopant level within the band gap. Incorporation of nitrogen anion species was confirmed by N 1s X-ray photoelectron spectroscopy. In the case of visible light irradiation (400 nm and higher), the NT particles showed photocatalytic activity for oxidative decomposition of acetic acid in the presence of iodate anion (IO3-) as an electron acceptor, while a commercial TiO2 showed no photocatalytic activity under similar photoirradiation conditions. The fact that the photocatalytic reaction occurred negligibly over NT particles in the absence of IO3- indicates that IO3- acts as an electron acceptor in the visible-light-induced photocatalytic reaction and retards recombination of photo generated carriers in the NT particles.
  • H. Iwai, K. Mizuta, A. Yamamoto, H. Yanagi, Yoshida
    2008 年 33 巻 1 号 p. 177-180
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Photoluminescence (PL) properties have been studied for electrodeposited porous ZnO thin films hybridized with luminescent rare earth metal complexes and organic molecules. Nanoporous ZnO films were cathodically electrodeposited from the bath containing eosin Y (EY). Various bridging ligands (BLs) having carboxylic acid group as anchor was loaded to ZnO. These BLs have the moiety to coordinate to metal ions and thus can form complexes on ZnO surface by uptaking metal ions such as Eu3+, Tb3+ and Al3+. Fluorescent organic molecules having carboxylic acid group has been chosen and are also attached from their solutions. Some of the hybrid thin films with metal complexes exhibited PL, while none of organic molecules showed PL. Especially efficient were the films with Eu3+ complexes. Its PL intensity was further increased by capping Eu3+ with -diketones. The quantum efficiency for its PL was determined as 21 %when only the ligand to metal energy transfer is taken into account.
  • Kunio Hashimoto, Manabu Kiguchi, Tatsuya Konishi, Kei Murakoshi
    2008 年 33 巻 1 号 p. 181-184
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    We have investigated the conductance of a single 4,4'-bipyridine molecule anchored on Au electrodes under electrochemical potential control. Appearance of the peak in the conductance histogram suggests the formation of a single molecular junction. The conductance of the single 4,4'-bipyridine molecular junction was estimated from the peak value of 0.01 G0 (G0=2e2/h) in the histogram. The conductance of the molecular junction did not change with the electrochemical potential. On the other hand, the intensity of the 0.01 G0 peak in the conductance histogram decreased as the potential of the Au electrode scanned from 0.2 V to -0.4 V vs. Ag/AgCl. The electrochemical potential dependence of the intensity of the peak in the conductance histogram could be explained by the change in the adsorption properties of 4,4'-bipyridine on the Au electrode.
  • Taichi Arakawa, Tsuyoshi Akiyama, Sunao Yamada
    2008 年 33 巻 1 号 p. 185-188
    発行日: 2008年
    公開日: 2020/03/17
    ジャーナル オープンアクセス
    Fabrication of silver nanoparticle (AgP) - polyion alternate films were successful by using layer-by-layer technique. Alternate films of AgPs and polyion were fabricated as follows. First, a quartz glass substrate or an indium-tin-oxide (ITO) substrate was poured into the solution of polyethyleneimine (PEI) and then polystylenesulfonate (PSS). Then, the PSS/PEI- modified substrate was dipped into the solution of PEI and AgPs to give alternate assemblies of AgP-PEI on the PEI/PSS substrate. Adsorption of AgPs was characterized by transmission absorption spectroscopy and quartz crystal microbalance measurements. Morphologies of films were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. These results indicate the achievement of stepwise adsorption of AgPs and the formation of layer-by-layer structure. It was also observed that the films fabricated on the ITO electrode showed appreciable photocurrent based on photoexitation of AgPs.
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