JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Print ISSN : 0021-9592
Volume 37 , Issue 5
Special Issue for Recent Progress on Molecular Assemblies Design and Novel Structures in Liquid Phase
Showing 1-18 articles out of 18 articles from the selected issue
  • Makoto Harada
    Type: Journal Review
    2004 Volume 37 Issue 5 Pages 577-587
    Published: 2004
    Released: August 28, 2004
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    Self-assembly of building blocks from solutions into ordered arrays is a promising approach toward functional materials. However, self-assembly alone forms locally ordered structures. The processing to enhance ordering is necessary for real world applications. This article presents an overview of current research activities in order-enhancing processing. The first part discusses the processing needed for controlling microdomain orientations and macroscale-ordering in block copolymer systems. The second part is concerned with the processing needed for creating two and three dimensional ordered arrays from colloidal suspensions. Understanding of the underlying physical-nature in the order-enhancing processing will provide a scientific platform in the chemical engineering field.
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  • Hideto Matsuyama, Kazuhiro Ohga, Taisuke Maki, Masaaki Teramoto
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 588-591
    Published: 2004
    Released: August 28, 2004
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    Honeycomb patterned polystyrene film was prepared from a polystyrene chloroform solution including polyion complexes by solvent evaporation under high atmospheric humidity. Formation of the honeycomb pattern was owing to the hexagonally packed water droplets which condensed onto the polymer solution. The pore diameter and the pore depth of the honeycomb pattern were remarkably influenced by the polystyrene molecular weight. A light scattering experiment was conducted to follow the structure formation process. The change of the lattice constant was explained by the behavior of water droplets.
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  • Masahiro Yoshida, Tsutomu Matsui, Yoshimitsu Uemura, Yasuo Hatate
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 592-596
    Published: 2004
    Released: August 28, 2004
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    Nylon-polystyrene microcapsules sensitive to outside stimuli such as an external electric field were prepared by the combination of interfacial polymerization and solvent evaporation techniques. A ferroelectric liquid crystal monomer possessing both the mesogenic group and chirality was much effective as a functional component which responds to an external electrical field. The liquid crystal is extremely sensitive to the outside stimuli, because it has spontaneous polarization. The microcapsules immobilizing the liquid crystal could control the permeability of oxprenolol, which is used as an encapsulated core material, compared to that of the microcapsule without liquid crystals under the external intermittent electrical field. In addition, we characterized the electro-responsive controlled release mechanism by the polarized light transmittance measurement.
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  • Takehiko Gotoh, Yoshio Maeda, Yuko Nakatani, Shuji Sakohara
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 597-603
    Published: 2004
    Released: August 28, 2004
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    Thermosensitive porous, cylindrical gel was synthesized by radical polymerization of N,N-diethylacrylamide (DEAA) as primary monomer and N,N′-methylenebisacrylamide as cross-linker. The synthesis was done at various temperatures above the LCST of poly-DEAA, about 32°C. The pore size distributions of these gels were measured by the solute exclusion method, and the swelling behavior of these gels was investigated. The volume fraction of the pores larger than 100 nm remarkably increased by synthesizing above 40°C. In other words, the porous structure developed. The gel synthesized at 37°C, i.e. near the LCST of poly-DEAA, largely deformed in the swelling process. On the other hand, the gels synthesized at 50°C swelled without deformation, in other words, retaining the cylindrical shape, and the swelling rate was inversely proportional to the square of the diameter of the gel. These swelling behaviors were discussed from the pore size distribution and the elastic modulus of these gels.
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  • Motonari Adachi, Koichi Mori, Yasuo Sato, Lihua Pei
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 604-608
    Published: 2004
    Released: August 28, 2004
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    Gold nanowires with a 2-dimensional network structure were formed by controlling the concentration of reductive reagent in the synthetic method for gold nanoparticles. Transmission electron microscopy images clearly showed the formation of a network structure of gold nanowires. Fusion of gold nanoparticles was confirmed by TEM images taken after the treatment of the water-soluble thiol compound, which could separate all gold nanomaterials to individual ones. The resistance of the dip-coated gold nanowire films was around 1 ohm/cm after removing gelatin by calcination.
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  • Tomokazu Tanase, Akira Watanabe, Yoshio Kobayashi, Mikio Konno, Takao ...
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 609-613
    Published: 2004
    Released: August 28, 2004
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    Lead zirconate titanate (PZT) thin films seeded with barium strontium titanate (BST) nano-crystalline particles were fabricated on a Si wafer with a spin-coating technique. The BST particles synthesized with a sol-gel method were dispersed in an acetylacetone (chelating reagent) modified PZT precursor solution of complex alkoxides for the fabrication. The micro-patterns of the PZT film containing 50 mol% BST particles could be obtained by the direct photo-irradiation to the fabricated films for 40 min without any pre-heating treatments, while the PZT films in the absence of the BST particles required pre-heating treatment at 200°C for 10 s before the photo-irradiation. This suggested that the BST crystallines accelerated decomposition of the chelate compounds and subsequent polycondensation of PZT alkoxides.
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  • Yoshio Kobayashi, Hiroyuki Miyauchi, Shunchao Gu, Daisuke Nagao, Mikio ...
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 614-621
    Published: 2004
    Released: August 28, 2004
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    This paper describes fabrication of well-ordered mono- and multi-layers of submicron-sized silica or polystyrene (PSt) spheres. The mono-layers of spheres were fabricated on glass plates by a dip-coating technique at various concentrations of KCl, HCl and KOH in colloidal suspension. The mono-layer of spheres in a close-packed hexagonal structure showed an extinction peak in the visible wavelength attributed to a secondary Bragg diffraction. Full width at half maximum (FWHM) of the extinction peak was the lowest at low ionic strength and at neutral pH. Different types of multi-layers of spheres were fabricated by repeating the dip-coating processes. Silica spheres with a size of 589 nm could be mono-layered in the close-packed hexagonal structure on the mono-layer of the 404-nm-PSt spheres. PSt spheres with a size of 404 nm could be layered on the mono-layer of 500-nm-PSt spheres in such a way that the 404-nm-PSt spheres occupied void spaces among three 500-nm-PSt spheres. Silica spheres with a size of 233 nm could be assembled in a two-dimensional network structure on mono-layered 589-nm-silica spheres.
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  • Carlos Rodriguez, Durga P. Acharya, Alicia Maestro, Koheita Hattori, K ...
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 622-629
    Published: 2004
    Released: August 28, 2004
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    The phase behavior, microstructure and rheological properties of mixtures of polyoxyethylene type nonionic surfactants (C12EOn, n = 0–4) and alkyltrimethylammonium bromide cationic surfactants in water were investigated. Upon addition of C12EO3 to the aqueous cationic system at high surfactant concentration, both the interfacial curvature of aggregates and the effective cross-sectional area per surfactant molecule, aS, decrease, resulting in a hexagonal-lamellar liquid crystal phase transition. This effect becomes more pronounced as the alkyl chain-length of the cationic surfactant increases. At low surfactant concentration, addition of nonionic amphiphile to micellar solution above a particular concentration, C*, induces a rapid unidimensional micellar growth, and particularly in CTAB systems viscoelastic micellar solutions of entangled wormlike micelles are formed. With successive addition of the nonionic amphiphile ultimately a micellar to lamellar phase transformation occurs. Rheological measurements within the Wm-phase show that with decreasing EO chain-length, C* also decreases and viscosity increases more swiftly with increasing concentration of nonionic amphiphile, suggesting a rapid micellar growth. This is attributed to the decrease in aS, as predicted by a simple geometrical model.
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  • Yoshikazu Miyake, Hiromi Tada
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 630-635
    Published: 2004
    Released: August 28, 2004
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    Metal-doped mesoporous titania was obtained by aging a mixed solution of metal salt, polyacrylic acid (PAA) as a template and titania sol, which had been prepared by disolving titanium tetraisopropoxide (TTIP) in hydrochloric acid solution, at 333 K for 24 hours. All the metal-doped mesoporous titania were prepared from the gel solution and the crystal structure was anatase. The diffuse reflectance spectra of the metal-doped titania powder show to absorb the visible light. The metal-doped mesoporous titania powder was dispersed in an aqueous methylene blue (MB) solution and the adsorption and photodegradation of MB were characterized. The MB concentration was decreased to one-twentieth the initial concentration (48 μm) after about 15 minutes with W-doped mesoporous titania under irradiation of white light. The rapid decrease at the initial stage was caused by the adsorption, and after about 30 min products of the photocatalytic degradation of MB were observed. However, for the Fe- and Cu-doped mesoporous titania adsorbed MB in the initial stage, but the photocatalytic degradation of MB almost did not proceed.
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  • Ken-ichi Kurumada, Masataka Tanigaki, Lihua Pei, Naoki Sugitani, Keiji ...
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 636-644
    Published: 2004
    Released: August 28, 2004
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    The extraction behavior of phenol by extractant TBP (tributyl phosphate) into perfluoroalkane (Florinert®) was studied in the partition equilibrium of phenol. The intrinsic nano-scale solution structure of Florinert containing alkane and TBP was deduced from the results of the dynamic light scattering measurements. The solubility and extracting ability of TBP were found to be greatly enhanced by the presence of alkane dissolved in Florinert. Dynamic light scattering revealed that n-hexane dissolved in Florinert FC-72 formed nano-scale clusters. These nano-scale clusters were so small that the perfluoroalkane phase was optically transparent, however, they dominantly promoted the solbilization of extractant TBP in perfluoroalkane and increased the partition ratio of phenol in the perfluoroalkane phase. Since TBP molecules need to behave collectively to extract a phenol molecule, those nano-clusters of n-hexane molecules are considered to offer TBP molecules nano-scale spaces necessary for them to act in a grouped fashion. Extractant TBP molecules cannot work effectively for the extraction of phenol in the case where they are alone in perfluoroalkane. Extraction behavior of oil phases which are mainly comprised of perfluoroalkane is largely determined by the nanoscopic structures additives which dominantly contribute to the extraction. Therefore, the function of the additive (n-hexane) entirely differs from that in the case of conventional mixed-solvent systems from the viewpoint of their extraction mechanism.
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  • Keiji Ishikawa, Ching-Ju Wen, Koichi Yamada, Tatsuya Okubo
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 645-649
    Published: 2004
    Released: August 28, 2004
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    To evaluate the effect of the surface plasmon resonance of Ag nanoparticles on dye-sensitized solar cells, we measured the photocurrent of electrochemical cells using dense dye-adsorbed TiO2 thin films with and without Ag nanoparticles at different adsorbed-dye concentrations. At lower dye concentrations, the photocurrent of the cells with Ag was found to be enhanced by the effect of the surface plasmon resonance compared to that of the cells without Ag. On the other hand, the photocurrent of the cells with Ag decreased at higher dye concentrations, which was caused by increased trap levels and band-edge fluctuations with Ag incorporation. It is revealed that the control of the structure and quantity of Ag particles is important to apply the surface plasmon resonance effect to dye-sensitized solar cells.
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  • Akihisa Shioi, Zhang Yan Lin
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 650-656
    Published: 2004
    Released: August 28, 2004
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    An experiment for the particle growth in gelatin was performed. Particle is a solid solution of (Ba,Sr)SO4. First of all, we performed a counter-diffusion type experiment where BaCl2 and SrCl2 diffuse in gelatin and Na2SO4 diffuses toward the opposite direction. This is a condition proposed by Putnis et al. (1992). Oscillatory zoning found out by Putnis et al. (1992) was reproduced. Then, chemical composition changed periodically in a particle, thickness of each circular stripe being several microns in the order of magnitude. In order to investigate the particle growth process in a gel, we performed experiments for particle growth with several kinds of processes with reactions and diffusions. In these experiments, some kinds of chemical species were dissolved in gelatin, and other chemical species were diffused in gelatin. Findings of this work indicated that core portions of particles of the reaction-diffusion process were mainly composed of BaSO4 which determines fundamental shape of particles. After formation of this core, hemi-cylindrical portions with Sr-rich composition were deposited on the surface of the core. Although the characteristics were always kept for all of the experimental conditions of this work, the rate of deposition of hemi-cylindrical portion was dependent on the way of diffusion which was controlled by an experimental setup and gelation time. Fundamental information for particle growth in gel was obtained in this work, and potential activity for particle formation with reaction-diffusion mechanism was pointed out.
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  • Yasushige Mori, Kei Zaitsu
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 657-661
    Published: 2004
    Released: August 28, 2004
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    A droplet of a colloidal suspension of 250 nm polystyrene latex particles was observed during evaporation from plates with different contact angles (20, 87 and 104°) and the behavior of the droplet was evaluated. When the edge of the droplet did not recede towards the center during the evaporation process, the particles were observed to aggregate at the edge of the droplet forming a ring-like deposit. This ring-like deposit had an opal color, and that is thought to be a result of its highly ordered array structure. The highly ordered structure was obtained when the droplet was deposited on a hydrophilic plate with a 20° contact angle. In addition, a highly ordered array was observed in the droplet upon evaporation on a hydrophobic plate with an 87° contact angle, when particles were dissolved in a solution with a high ionic strength. This observation was explained by the DLVO theory.
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  • Masahiro Goto, Ayumi Momota, Tsutomu Ono
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 662-668
    Published: 2004
    Released: August 28, 2004
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    Deoxyribonucleotide (DNA) was successfully extracted in a few hours by reverse micelles, which were formed and functionalized by a cationic quaternary ammonium surfactant in isooctane. Several parameters which affect the DNA transfer from an aqueous phase to a reverse micellar phase, such as the natures of a surfactant and a solvent, salt concentration in a feed solution, and hydrophobicity of micelles, were investigated. The use of a cationic surfactant was found to yield a high transfer rate of DNA into reverse micelles. We have attributed the DNA transfer to the electrostatic interaction between the cationic surfactant and the negatively charged DNA. We found that the higher the hydrophobicity of a surfactant used to form micelles, the better the DNA transfer efficiency in the forward extraction. Preferential extraction of DNA was achieved by using twin long-alkyl chains of cationic surfactants. However, pH in the aqueous feed solution did not affect the extraction performance of reverse micelles. On the other hand, alcohol, as a co-solvent plays an important role in the back extraction of DNAs. Complete back-extraction of DNAs was achieved without any conformational change by adding an appropriate alcohol to the reverse micellar phase.
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  • Toru Wakihara, Tatsuya Okubo
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 669-674
    Published: 2004
    Released: August 28, 2004
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    Seeded growths of faujasite and zeolite A were investigated by atomic force microscopy (AFM). For seeded growth, clear aluminosilicate solutions (90Na2O:xAl2O3:9SiO2:5760H2O, where x = 0.1–1.0), which are useful for faujasite or zeolite A growth on seeded faujasite or zeolite A, respectively, were prepared at 353 K. Changes at the same position were observed along with growth period, and it was revealed that crystal growth behaviors of faujasite and zeolite A were different in the same aluminosilicate solution. Corresponding aluminosilicate solutions were characterized by Raman spectroscopy. By combining the results of both AFM and Raman spectroscopy, the behavior of aluminosilicate species incorporating into the solid phase from the liquid one was discussed. Key precursors of crystal growth for faujasite and zeolite A were proposed to be six-membered and four-membered rings, respectively.
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  • Takayuki Hirai, Yuichiro Nomura
    Type: Research Paper
    2004 Volume 37 Issue 5 Pages 675-679
    Published: 2004
    Released: August 28, 2004
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    The photoluminescence from Mn2+-doped ZnS (ZnS:Mn) nanoparticles prepared in an AOT/isooctane reverse micellar system was investigated. The composition (Mn content) and photoluminescent properties of the nanoparticles depend on the composition of the feed solution and the water content (Wo) of reverse micellar solution. The emission intensity from Mn2+ ions at 580 nm depends mainly on the Mn content in the nanoparticles rather than the nanoparticle size, when the nanoparticle size is controlled by varying the Wo value at a constant feed composition of Zn and Mn.
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  • Chengzhou Li, Makoto Yoshimoto, Kimitoshi Fukunaga, Katsumi Nakao
    Type: Short Communication
    2004 Volume 37 Issue 5 Pages 680-684
    Published: 2004
    Released: August 28, 2004
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    A commercial cellulase was entrapped in liposomes composed of phosphatidylcholine (65 mol%), 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (5 mol%) and cholesterol (30 mol%) to prepare the cellulase-containing liposomes (CL) with the enzyme incorporated as much as possible into the membrane. The CL was then immobilized with chitosan gel beads to develop an efficient biocatalyst for enzymatic hydrolysis of cellulose. The activity of the CL prepared was determined with the membrane impermeable substrates such as insoluble filter paper (FP) and soluble carboxymethyl cellulose (CMC). The activity for FP was only several percents of that for CMC. The activity efficiency of the CL for either substrate was found to be about 5%, which suggests that around 5% of the whole cellulase contained in the CL were incorporated in the outer membrane of the liposomes. The CL was coupled with the glutaraldehyde-activated chitosan gel beads to obtain the immobilized cellulase-containing liposomes (ICL). The ICL was repeatedly used in the hydrolysis of both CMC and FP to examine its operational stability. The stability of the ICL was also compared to that of a conventionally immobilized cellulase (IC). As a result, although the activity of the ICL for FP or CMC decreased to 30% or 85%, respectively of the initial activity in its first use, the ICL almost maintained the respective activity for its subsequent uses. The activity of the IC for either substrate decreased steadily from around 70% to 50% of the initial one with the repeated use.
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  • Yukiko Marui, Masakuni Matsuoka
    Type: Short Communication
    2004 Volume 37 Issue 5 Pages 685-689
    Published: 2004
    Released: August 28, 2004
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    As a fundamental study of zeolite crystallization from aluminosilicate solutions, the critical radii of nuclei of zeolite A and the amorphous phase were estimated based on the nucleation rates determined in our previous studies and the classical theory of homogeneous nucleation.
    The calculated critical radii of nucleus of zeolite A crystals were 0.4–0.8 nm under the conditions examined, and its diameter is found to be almost equal to the half of the edge length of a unit cell of zeolite A crystals. Meanwhile the radii of the critical nucleus of the amorphous phase were 0.8–1.6 nm with the surface energy of 12–23 mJ·m–2.
    These calculated results imply the following phase transformation processes. For the case of zeolite A nucleation, several growth units assemble together and result in a formation of a zeolite A nucleus. In the case of the amorphous phase, a greater number of growth units are needed for nucleation and the induction time of the nucleation of the amorphous phase is shorter than that of zeolite A probably due to the random structures of the amorphous phase.
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