| POLYMERS Vol.72 No.12 |
| >> Japanese | >> English |
COVER STORY
Front-Line of Analytical Techniques Supporting Polymer Sciences: Special Issue on Local Structure Analysis |
| COVER STORY: Highlight Reviews |
| Cryo-EM Observations of Soft-Materials | Tasuku HAMAGUCHI |
| <Abstract> Observation and structural analysis of soft materials using cryo-electron microscopy can potentially observe liquid materials without modification. In addition to the conventional cryo-EM observation using water as a solvent, it is also possible to observe the material in an amorphous state of organic solvent. In this study, we demonstrated the shape and concentration dependence of micelles formed by surfactants in detergents. Keywords: Cryo-Electron Microscopy / Soft-Materials / Micelle / Surfactants |
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| Polymer Nanomechanics by Atomic Force Microscopy | Ken NAKAJIMA |
| <Abstract> This article reviews the latest topics related to atomic force microscopy (AFM). The latest AFM technologies that may be applied to polymer research, such as 3D-AFM, FM-AFM, AM-FM mode, high-speed AFM, simulation techniques, and viscoelasticity measurement will be reviewed. To do so, I would like to take the way to introduce my experience at the MultiFrequency AFM international conference that I attended this year. Keywords: Atomic Force Microscopy / Frequency-Modulation AFM / High-Speed AFM / Viscoelastic Measurement |
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| COVER STORY: Topics and Products |
| Highly Spatial-Resolved SEM-EDS Imaging Analysis of Nanocarbon Materials | Hideaki NAKAJIMA, Toshiya OKAZAKI |
| <Abstract> Energy-dispersive X-ray spectroscopy (EDS) in scanning electron microscopy (SEM) is a type of elemental analysis used universally. Due to its wide scanning field of view, it is particularly suited to the evaluation of heterogeneities in bulk materials. However, the spatial resolution of SEM-EDS is usually limited to approximately 1 mm by electron scattering, which makes imaging analysis of nanomaterials composed of light elements (i.e., C and O) difficult. Recently, we have successfully improved the spatial resolution of SEM-EDS analysis to below 10 nm, enabling high-precision imaging evaluation of the surface state of carbon nanotubes (CNTs). Here, we briefly introduce the CNT material and explain the developed high spatial resolution SEM-EDS technique. Keywords: SEM / EDS / CNT |
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| Nanoendoscopy AFM for Visualizing the Inside of Living Cells | Takeshi FUKUMA |
| <Abstract> Understanding biomolecular nanodynamics inside living cells is key to elucidating fundamental mechanisms of various life phenomena. However, nanoscale phenomena directly observable by the current technologies are very limited. Since atomic force microscopy (AFM) is the only method that allows direct observation of the nanodynamics of proteins in liquid, it is one of the most promising candidates to solve the aforementioned problem. However, previous high-resolution bio-AFM imaging was mostly performed to observe the biomolecular systems reconstructed on a solid substrate. Thus, it has often been questioned if the results truly represent the intracellular structures or dynamics. To overcome this limitation, we recently developed nanoendoscopy AFM, where a needle-like probe is inserted into a live cell, and the force applied to the probe is detected for visualizing intracellular nanodynamics. Here we introduce the basic principle of this method and examples of its applications. Keywords: Atomic Force Microscopy / Nanoendoscopy AFM / Live Cell Imaging |
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| Exploring the Bonding Mechanism of Adhesive Interfaces through in-situ Failure Analysis by Scanning Transmission Electron Microscopy | Shin HORIUCHI |
| <Abstract> The nano-scale failure behaviors of joint interfaces were investigated using an in-situ straining technique under a scanning transmission electron microscope (STEM). This technique allowed us to observe the propagation of cracks with high spatial resolution. We used a specially designed specimen holder to subject the thin sections of bonded interfaces to tensile loading. We observed the deformation process in the nanometer scale, including pre-cracking before deformation and crack initiation at the crack tip. We investigated the failure of aluminum alloy (Al5052) and epoxy adhesive. These investigations aimed to demonstrate the different stages prior to macroscopic fracture of the interfaces. An innovative in-situ straining technique, coupled with high-resolution and high-contrast imaging by STEM, enabled us to observe micro deformations preceding crack propagation, microvoid formation prior to crack progression, and failure of the surface-modified layer on the aluminum surface. Keywords: In-Situ STEM / Bonding / Interface / Crack / Fracture |
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| Multi-Scale Analysis for Membrane Electrode Assembly of Polymer Electrolyte Fuel Cell by Electron Microscopy | Ryoma ARITA, Sachi IKEMOTO, Takuji UBE |
| <Abstract> Polymer electrolyte fuel cells (PEFC) are expected to be successful as one type of the technologies to realize the carbon neutral energy generation for mobility without emitting CO2 gas. The understanding of complex microstructures of the membrane electrode assembly (MEA) as the key component of the PEFC is the essential to improve its power generation ability. Ultra-low acceleration voltage scanning electron microscopy (ULV-SEM) and scanning transmission electron microscopy (STEM) can reveal the microstructures of a MEA in multi-scale, i.e., from the micron scaled overall structure of the catalyst layer to the atomic scaled catalyst materials. Especially, focused ion beam (FIB) – SEM serial-sectionning and STEM tomography techniques provide three-dimentional micro-structural information of an MEA, which directly relates to the transport phenomenon of gas, water, protons and electrons. In this report, we demonstrate some results of multi-scale analysis for the MEA of PEFCs by SEM and STEM. Keywords: Carbon-Neutrality / PEFC / MEA / ULV-SEM / STEM / Fuel Cell / Tomography / Multi-Scale |
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| Polymer Science and I: A Personal Account |
| Eyes on the Inside | Toyoaki HIRATA |
| <Abstract> When I realized the joy of “seeing” the invisible molecular world through the eyes on the inside based on the experimental results of spectrocopic techniques, my career as a researcher started. Now, I will continue trying to contribute to the development of polymer chemistry, even if only in a small way. |
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| Front-Line Polymer Science |
| Recent Progress in X-ray Phase Tomography | Atsushi MOMOSE |
| <Abstract> Conventional X-ray imaging and tomography that rely on X-ray absorption contrast are routinely used to visualize inner structures. However, absorption contrast has a drawback that the sensitivity to materials consisting of low-Z elements, such as polymers and biological tissues, is poor. X-ray phase imaging and tomography have attracting attention because the sensitivity to low-Z materials are considerably improved because the phase interaction is much larger than the absorption interaction. Here, recent progress in this field is reviewed especially by introducing hierarchal X-ray phase tomography performed for human organs and tensor tomography applied to a CFRP sample. The former enabled viewing the entire body of organs and zooming up to the cellular level at any local position. The latter enabled three-dimensional visulalization of fiber orientation without resolving each fiber. Keywords: X-Ray CT / Phase Contrast / Tensor Tomography / CFRP |
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