| POLYMERS Vol.60 No.6 |
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COVER STORY
Fusion of Metals and Organic Materials |
| COVER STORY: Highlight Reviews |
| Catalysis by Gold Clusters Supported on Polymers | Tamao ISHIDA and Masatake HARUTA |
| <Abstract>
Gold exhibits unique catalysis at low temperatures when
it is deposited as nanoparticles smaller than 5 nm on base metal oxides.
On the other hand, polymer supports require gold to be tiny clusters
smaller than 2 nm to be catalytically active for liquid phase oxidation
and reduction reactions. A soft catalytic filter for air purification
has recently been developed by depositing gold nanoparticles onto the
surfaces of base metal oxide layers which cover PET unwoven fibers. Keywords: Gold Nanoparticles / Gold Clusters / Polymer Supports / Catalysis / Alcohol Oxidation / N-Alkylation |
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| Thermo-Responsive Magnetic Nanoparticles for Biomedical Applications | Akihiko KONDO and Noriyuki OHNISHI |
| <Abstract> In
recent years, magnetic nanoparticles have been actively studied due to
their wide range of biomedical applications in both in vitro and in
vivo.
Especially, the combination of magnetic nanoparticles with stimuli-responsive
polymers is very effective to obtain nanoparticle systems which are able
to respond to environmental changes and magnetic field and have high
composite stability and chemical functionality for biomolecule attachment.
Thermo-responsive systems are the most studied stimuli-responsive systems
due to the fact that this parameter is easy to control and directly related
with the human body. This paper descries a survey of the recent literatures
on various stimuli-responsive magnetic nanoparticles, our development
of thermo-responsive magnetic nanoparticles and their potential applications
to biomedical measurements, bioseparations and drug delivery systems. Keywords: Magnetic Nanoparticles / Thermo-Responsive Polymers / Biomedical Measurements / Bioseparations / Drug Delivery Systems / Biomedical Applications |
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| Precise Synthesis of Metal Clusters in a Dendrimer Template | Takane IMAOKA and Kimihisa YAMAMOTO |
| <Abstract> Metallodendrimers
based on a fine-controlled metal-assembly with a defined molecular weight
and structure act as a molecular template for the fine synthesis of metal
clusters and metal-oxide clusters. These clusters with a size of less
than 1 nm exhibit significantly different properties. Keywords: Dendrimers / Phenylazomethines / Metal Complexes / Supramolecules / Metal Clusters / Metal Oxide Clusters / Catalysis / Quantum-Size Effect |
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| Adaptive Self-Assembly of Coordination Nanoparticles Formed in Aqueous Media and Their Functions | Ryuhei NISHIYABU and Nobuo KIMIZUKA |
| <Abstract> Amorphous
nanoparticles of coordination polymer networks are spontaneously self-assembled
from nucleotides and lanthanide ions in water. They show intrinsic functions
such as energy transfer from nucleobase to lanthanide ions and excellent
performance as contrast enhancing agents for magnetic resonance imaging
(MRI). Furthermore, adaptive inclusion properties are observed in the
self-assembly process: functional materials such as dye molecules, inorganic
nanoparticles, and proteins are facilely encapsulated. Photoluminescence
dyes confined in the coordination nanoparticles are conformationally
restricted and surprisingly stable against molecular oxygen. Incorporation
of quantum dots (QDs) in the coordination networks provides photoluminescent
core-shell nanoparticles. The binding of proteins to the coordination
networks provides a new approach in the protein immobilization. Incorporation
of glucose oxidase (GOD) and horse radish peroxidase (POD) provides coordination
nanoparticles that exhibit their enzymatic activity. The concept of adaptive
self-assembly will be extended to a wide range of molecular self-assembling
systems and would exert significant influences in nanomaterials science. Keywords: Self-Assembly / Adaptive Self-Assembly / Nanoparticles / Coordination Polymer |
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| COVER STORY:Topics and Products |
| Preparation of Metal Nanoparticles Highly-Dispersed in Ionic Liquids and Their Application to Photo-Functional Materials | Ken-ichi OKAZAKI and Tsukasa TORIMOTO |
| <Abstract> Ionic
liquids (ILs) have an extremely low vapor pressure that enables the handling
of ILs under vacuum. The sputter deposition of gold onto ILs resulted
in the formation of a solution containing highly dispersed Au nanoparticles.
Thus-obtained nanoparticles were densely immobilized on a glass substrate
surface-modified with imidazole functional groups. Photoexcitation of
the surface plasmon resonance peak of Au particle films caused enhancement
of the photoluminescence of CdTe quantum dots. Keywords: Ionic Liquid / Nanoparticles / Sputter Deposition / Surface Plasmon |
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| Coordination Nanospaces for Controlling Polymer Synthesis and Properties | Takashi UEMURA |
| <Abstract> Metal-Organic
Frameworks composed of metal ions and organic ligands have been extensively
studied. Use of their regulated and tunable nanochannels for a field
of polymerization allows multi-level controls of polymerization. In addition,
polymers confined in these channels show unique properties based on only
a few-chain assembly. Keywords: Metal Organic Frameworks / Nanochannel / Controlled Polymerization / Polymer Property |
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| Membrane Emulsification Using Anodic Porous Alumina | Takashi YANAGISHITA |
| <Abstract> There
has been increasing interest in the fabrication of uniform sized polymer
particles from the micrometer to nanometer scales because of their applicability
to the various types of functional devices. In this report the fabrication
of monodisperse polymer particles by membrane emulsification using highly
ordered anodic porous alumina is described. Keywords: Anodic Porous Alumina / Nanoparticle / Membrane Memulsification |
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| Fine Structural Control of Metal Nanoparticles / Polymer Nanocomposites | Kensuke AKAMATSU |
| <Abstract> Hybrid
nanocomposites containing metal nanoparticles dispersed in polymer matrices
have attracted much attention recently in various technological fields.
Properties of these new materials are strongly dependent on their microstructure,
e.g., size, size distribution, and interparticle spacing of the dispersed
nanoparticles. A technique that allows precise control over film microstructure
is, therefore, indispensable for the preparation of nanocomposites with
desired properties. Keywords: Metal Nanoparticle / Nanocomposites / In Situ Synthesis / Particle-to-Particle Interaction |
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| Porous Protein Crystals Designed for Metal Complexes | Takafumi UENO |
| <Abstract> Protein
crystals have attracted much attention as solid materials. Our present
works demonstrate that protein crystals can be employed as porous bio-materials by site-specific modifications, in the accumulation of metal ions, and for the integration of various metal complexes. Keywords: Protein Engineering / Protein Crystals / Self-Assembly / Biomineralization / Electron Transfer |
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| Growing Polymers: A Personal Account |
| Polymer Chemistry Covers All Aspects of “Helix” and “Crayfish” | Tatsuya NISHIMURA |
| <Abstract> Postdoctoral researchers should try to switch their focuses between graduate school and postdoctoral period to improve their development capacity. When I joined Kato laboratory as a postdoctoral researcher, I changed the direction of my research field from helical polymers to a crayfish. I realized that the underlying science of both fields is polymer chemistry. |
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| Great Experience in the USA | Akari HAYASHI |
| <Abstract> My research life is really based on great experience in the USA. I have intentionally learned various research subjects during my Ph.D. and postdoctoral work, and then developed an independent project, a “Carbon nanoreactor”. |
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| Front-Line Polymer Science |
| Structure Analysis of Polymer Crystals Modernized with Quantum Beam Usage | Kohji TASHIRO |
| <Abstract> One
of the most significant progresses in the X-ray crystal structure analysis
technique is the utilization of a synchrotron high-energy X-ray source
which can give us a tremendously large number of reflections, making
it possible to find out even the hydrogen atomic positions with high
accuracy. The wide-angle neutron diffraction method is also important
for the extraction of hydrogen atomic positions as demonstrated in the
case study of fully-deuterated polyethylene. The so-called X-N (X-ray-neutron)
method has been also applied, which successfully clarified the bonded
electron density distribution along a polydiacetylene skeletal chain.
Detailed crystal structure analysis was performed also to observe the
mechanical deformation mechanism of a polymer crystal viewed on the atomic
level. Time-dependent rapid X-ray diffraction measurement has made it
possible to trace the structural change in a photo-induced solid-state
polymerization process. An organized combination of X-ray diffraction
methods with others such as infrared spectroscopy has shown to be important
for the study of structural evolution processes of polymer crystals. Keywords: X-Ray Crystal Structure Analysis / Wide-Angle Neutron Diffraction / Hydrogen Atomic Positions / High-Energy Synchrotron X-Ray Beam / Electron Density Distribution / X-N Method / Photo-Induced Solid-State Polymerization Reaction / Microscopic Deformation Mechanism |
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