POLYMERS Vol.62 No.11
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COVER STORY
Exploring Polymers with Cutting-Edge Visualization Techniques
COVER STORY: Highlight Reviews
How Complex is a Single DNA Molecule in an Aqueous Solution? Masateru TANIGUCHI
<Abstract> Information regarding 3D protein structure is essential for drug discovery, and detailed 3D structures can only be obtained by analyzing crystal structures, particularly by using the X-ray diffraction method on crystals. Single-molecule structural analysis technology, which does not require crystals, will allow high-throughput investigation of the relationship between proteins and diseases and bring about innovations that would advance drug discovery, the understanding of disease mechanisms, design of therapeutic strategies, and personalized medicine. Recently, 3D structure analysis methods for single molecules in solutions using nanopores have been developed, whereby single-molecule structures are determined by changes in ionic currents that pass through nanopores. In this study, we review recent advances in the single-molecule analysis of DNA molecules using solid-state nanopores.
Keywords: Single Molecules / Nanopores / Ionic Currents
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Recent Advances in Tomography
Recent Advances in Multi-Scale Tomographic Techniques in Polymer Research
Hiroshi JINNAI
<Abstract> This article summarizes recent advances in an emerging three-dimensional (3D) imaging technique, electron tomography. We will put particular emphasis on electron tomography for μm-size volume data with the spatial resolution of the order of 10 nm. This technique provides new insights into “meso-scale” structural information that has been lost over the past several years.
Keywords: Electron Tomography / Scanning Electron Microscopy / Meso-Scale Structural Observations / Three-Dimensional Image Analysis
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New Developments of Structural Analysis on Polymer Composite using Quantum Beam Hiroyuki KISHIMOTO
<Abstract> The hierarchical structure among wide spatiotemporal scale formed in polymer composeites relates to various functions. Material research with a quantum beam produces new knowledes in the process of functional material developments. In this article, I introduce the spatiotemporal structural analysis of polymer composites using a quantum beam.
Keywords: Synchrotron Radiation / SAXS / X-ray Imaging / XPCS / Dynamics / Polymer Composite
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COVER STORY: Topics and Products
Single-Molecules Imaging of Polymers Ken-ichi SHINOHARA
<Abstract> Direct observation of a polymer chain deepens the understanding about structure and the function. We succeeded in direct observation of the long-chain branch (LCB) structure in a low density polyethylene (LDPE). The sample is LDPE synthesized by the tubular process or the vessel process. The number, the length and the position of LCB were measured directly by an AFM in an organic solvent at room temperature. Single-molecules imaging of micro-Brownian movement in a chiral helical polymer was achieved by a fast-scanning AFM at room temperature. We measured the diffusion coefficient at each part in the polymer chain. It was estimated that this macromolecular motion was a dynamic multiple interactions and the Brownian movement at a solid/liquid interface, and based on the enthalpy entropy compensation. Furthermore, the macromolecular motor function was observed by a fast-scanning AFM. A molecule, which adsorbed to a chiral helical polymer having cholesteryl group [(-)-poly(ChOCPA)], was transported along the chain. This molecular transportation passed to long distances more than 100-nm and it was observed for long time that was more than four minutes.
Keywords: Single-Molecules Imaging / Polymer Chain / Brownian Movement / Enthalpy Entropy Compensation /
Polyolefine / Chiral Helix / Macromolecular Machine / Molecular Motor
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X-ray Phase Tomography Visualizing Three-Dimensional Phase Separation Structures Atsushi MOMOSE
<Abstract> Conventional X-ray imaging techniques that rely on absorption contrast are not usable effectively for polymer samples, which consist of low-Z elements with low X-ray absorbance. This problem can be overcome by using X-ray phase contrast. X-ray phase tomography is realized based on the phase-contrast techniques for highly sensitive three-dimensional polymer observation. Applications of X-ray phase tomography to polymer blend samples are demonstrated to reveal phase-separation structures, allowing quantitative analyses. Note that X-ray phase tomography is possible not only with synchrotron radiation but also with a laboratory X-ray source. In combination with an X-ray imaging microscpe, a spatial resolution of a micron has been achieved in three dimensions. In order to approach a time resolution of a second, X-ray phase tomography with white synchrotron radiation is also being developed; that is, four-dimentional phase tomography.
Keywords: X-ray Interferometry / Phase Contrast / Tomography / CT / Polymer Blend / Phase Separation
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Observation of Thin Films through Scattering Hideaki YOKOYAMA
<Abstract> Polymer thin film has been widely used for a variety of applications. However, observing the structure of thin films supported on substrates is still challenging. Recently Grazing Incidence Small Angle X-ray Scattering (GISAXS) emerged as an ideal tool to observe such thin film structures. However, GISAXS has to deal with complicated phenomena including transmission, refraction, and reflection in addition to scattering. Here, a brief and qualitative guide of GISAXS will be given primarily for novice and non- users of GISAXS.
Keywords: Scattering / GISAXS / Reflection / Refraction / Transmission / X-ray / Thin Films
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Visual Characterization of Nano-Sized Photoresist Pattern Formation Toshiro ITANI
<Abstract> Semiconductor down-scaling is reaching target pattern resolution sizes comparable to the polymer components of resist chemistry. For this reason, a re-thinking of present resist material and process concepts is crucial in meeting such stringent targets. To effectively do this, further fundamental research is necessary. One such fundamental point of interest is the understanding of photoresist dissolution during the development process. This article introduces the application of a high speed atomic force microscope optimized for the in situ characterization of the resist pattern formation process during development.
Keywords: Lithography / Resist / Process / Dissolution / Atomic Force Microscopy
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Scanning Helium Ion Microscope as the First Shared Research Equipment Keiko ONISHI
<Abstract> A Scanning helium ion microscope (SHIM) is a piece of equipment, which is suited to observe the surface morphology and chemistry on the nanometer scale. The SHIM has a good operability like a standard scanning electron microscope, as well as superior spatial resolution of several-score-times, high material contrast and depth-of-focus. Since insulating materials can be observed without coating, the SHIM can be a powerful tool for nano characterisation of insulating polymeric materials. Since the SHIM is a shared research equipment of the NIMS microstructural characterization platform, it can be used at a relatively low cost with a simple application procedure. Please feel free to make contact and consult with us.
Keywords: Ion Microscope / Surface Morphology / High Spatial Resolution / Insulator Observation / Shared Research Equipment
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Polymer Science and I: A Personal Account
By Trial and Error Akira MATSUO
<Abstract> This personal account reviews my experiences as a chemical researcher. To make a breakthrough, it is important to continue a process of trial and error without fear of mistake.
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Front-Line Polymer Science
Perspective of Bottom-up Surface-Assisted Polymerization Hiroshi SAKAGUCHI
<Abstract> Surface-assisted polymerization is a botton-up method to produce functional materials such as conjugated polymers on metal surface from molecular building blocks. By the use of this method, novel conjugated polymers with one and two dimensionally extended π-conjugation, which are applicable to the various fields such as electronics, photonics and energy sector, could be epitaxially grown along the lattice of metal as a template due to its strong interaction with molecules. This review describes the introduction of related researches reported so far and the future perspective of this approach from the view point of surface science and material science.
Keywords: Bottom-up / Surface Assisted Polymerization / Conjugated Polymers
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