58 results on '"Hiroshi Jinnai"'
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2. Kinetic Pathway of the Order–Order Transition from Hexagonally Packed Cylinder to Hexagonally Perforated Layer in Polystyrene-block-Poly(2-vinylpyridine) Using Time-Resolved 3D Transmission Electron Microtomography
- Author
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Hsiao-Fang Wang, Hironori Marubayashi, and Hiroshi Jinnai
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Inorganic Chemistry ,Polymers and Plastics ,Organic Chemistry ,Materials Chemistry - Published
- 2023
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3. Dislocation-Induced Defect Formation in a Double-Gyroid Network
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Tomohiro Miyata, Hsiao-Fang Wang, Takafumi Suenaga, Daisuke Watanabe, Hironori Marubayashi, and Hiroshi Jinnai
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Inorganic Chemistry ,Polymers and Plastics ,Organic Chemistry ,Materials Chemistry - Published
- 2022
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4. Ring-Filling Effect on Stress–Strain Curves of Randomly End-Linked Tetra-Arm Prepolymers
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Katsumi Hagita, Takahiro Murashima, Takahiro Ohkuma, and Hiroshi Jinnai
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Inorganic Chemistry ,Polymers and Plastics ,Organic Chemistry ,Materials Chemistry - Published
- 2022
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5. Structural Correlations of the Nonlinear Optical Response in Polydiacetylene Nanotubes Hybridized with Gold Nanoparticles
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Wakana Ito-Washiyama, Tsunenobu Onodera, Masaki Ageishi, Rodrigo Sato, Boyi Zhang, Satoshi Kato, Akito Masuhara, Hitoshi Kasai, Hiroaki Mamiya, Hiroshi Jinnai, Yoshihiko Takeda, and Hidetoshi Oikawa
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General Energy ,Physical and Theoretical Chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2022
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6. Nanoscale Stress Distribution in Silica-Nanoparticle-Filled Rubber as Observed by Transmission Electron Microscopy: Implications for Tire Application
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Tomohiro Miyata, Tomohiko Nagao, Daisuke Watanabe, Hiroshi Morita, Hiroshi Jinnai, Keizo Akutagawa, and Akemi Kumagai
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In situ ,Materials science ,technology, industry, and agriculture ,Stress distribution ,Silica nanoparticles ,Natural rubber ,Transmission electron microscopy ,visual_art ,Ultimate tensile strength ,visual_art.visual_art_medium ,General Materials Science ,Composite material ,Deformation (engineering) ,Nanoscopic scale - Abstract
Nanoparticle-filled rubber under tensile deformation was observed in situ by transmission electron microscopy (TEM), and the spatial distributions of the local maximum and minimum principal strains...
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- 2021
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7. Degradation of a Metal–Polymer Interface Observed by Element-Specific Focused Ion Beam-Scanning Electron Microscopy
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Katsunori Shimizu, Hiroaki Matsumoto, Miki Tsuchiya, Hiroshi Jinnai, Naoya Amino, Takashi Kakubo, and Akemi Kumagai
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Materials science ,Scanning electron microscope ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Focused ion beam ,law.invention ,Natural rubber ,law ,Electrochemistry ,General Materials Science ,Composite material ,Spectroscopy ,chemistry.chemical_classification ,Electron energy loss spectroscopy ,Vulcanization ,Surfaces and Interfaces ,Polymer ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,chemistry ,Electron diffraction ,visual_art ,visual_art.visual_art_medium ,Adhesive ,0210 nano-technology - Abstract
The degradation of a metal-polymer interface was studied in three dimensions using focused ion beam-scanning electron microscopy (FIB-SEM) with energy-dispersive X-ray spectroscopy. A brass-rubber interface, which is important for tires, was examined as an example of a metal-polymer interface. Brass-plated steel cords were embedded in rubber, which was then vulcanized. The brass-rubber interface was treated at 70 °C under 96% humidity for up to 14 days (a wet-heat aging treatment). FIB-SEM provided clear three-dimensional images of the adhesive layer consisting of brass (CuZn), CuxS, and ZnO/ZnS between the steel cords and rubber. During degradation, CuxS at the interfaces diffused into the rubber, resulting in the direct contact of bare steel with rubber. The lack of a substantial adhesive layer explained the degradation of mechanical properties after the wet-heat treatment. In addition, electron diffraction and electron energy loss spectroscopy revealed that the Cu2S crystals in the adhesive layer changed to crystal-like CuS during the degradation, which also caused a degradation of mechanical properties because a high Cu valence of x ≈ 2 in CuxS leads to stronger adhesion than a valence of x = 1.
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- 2020
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8. Strategy for Finely Aligned Gold Nanorod Arrays Using Polymer Brushes as a Template
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Hideyuki Mitomo, Yu Sekizawa, Yasutaka Matsuo, Satoshi Nakamura, Kuniharu Ijiro, Takeshi Higuchi, and Hiroshi Jinnai
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chemistry.chemical_classification ,Fabrication ,Materials science ,Cationic polymerization ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Surfaces and Interfaces ,Polymer ,Substrate (electronics) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Adsorption ,chemistry ,Electrochemistry ,General Materials Science ,Nanorod ,0210 nano-technology ,Nanoscopic scale ,Spectroscopy - Abstract
The development of a strategy for the assembly of nanoscale building blocks, in particular, anisotropic nanoparticles, into desired structures is important for the construction of functional materials and devices. However, control over the orientation of rod-shaped nanoparticles on a substrate for integration into solid-state devices remains challenging. Here, we report a strategy for the fabrication of finely aligned gold nanorod (GNR) arrays using polymer (DNA) brushes as a nanoscale template. The gold nanorods modified with cationic surface ligands were electrostatically adsorbed onto the DNA brush substrates under various conditions. The orientational behavior of the GNRs was examined by spectral analyses and transmission electron microtomography (TEMT). As a result, we found several important factors, such as moderate interaction between GNRs and polymers and polymer densities on the substrate, related to the vertical alignment of GNRs on the substrates. We also developed a purification method to remove the undesired adsorption of GNRs onto the arrays. Finally, we have succeeded in the fabrication of extensive vertical GNR arrays of high quality via the easy bottom-up process.
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- 2020
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9. Single-Macromolecular Level Imaging of a Hydrogel Structure
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Takayuki Nonoyama, Sedlacik Tomas, Jian Ping Gong, Ryuji Kiyama, and Hiroshi Jinnai
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Materials science ,Transmission electron microscopy ,Self-healing hydrogels ,Resolution (electron density) ,Direct observation ,Nanotechnology ,Nanometre ,Wetting ,Nanoscopic scale ,Macromolecule - Abstract
Hydrogels are promising materials for several applications, including cell scaffolds and artificial load-bearing substitutes (cartilages, ligaments, tendons, etc.). Direct observation of the nanoscale polymer network of hydrogels is essential in understanding its properties. However, imaging of individual network strands at the molecular level is not achieved yet due to the lack of suitable methods. Herein, for the first time, we developed a novel mineral-staining method and network fixation method for transmission electron microscopy observation to visualize the hydrogel network in its unperturbed conformation with nanometer resolution. Surface network observation indicates that the length of surface dangling chains, which play a major role in friction and wetting, can be estimated from the gel mesh size. Moreover, bulk observations reveals a hierarchical formation mechanism of gel heterogeneity. These observations have the great potential to advance gel science by providing comprehensive perspective that link bulk gel properties with nanoscale.
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- 2021
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10. Self-Assembled Morphologies of Lamella-Forming Block Copolymers Confined in Conical Nanopores
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Kookheon Char, Hiroshi Jinnai, Xiejun Hu, Youngkeol Kim, Akemi Kumagai, An-Chang Shi, and Baohui Li
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Materials science ,Nanostructure ,Polymers and Plastics ,Organic Chemistry ,02 engineering and technology ,Conical surface ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Self assembled ,Inorganic Chemistry ,Nanopore ,Lamella (surface anatomy) ,Chemical engineering ,Materials Chemistry ,Copolymer ,0210 nano-technology ,Nanoscopic scale - Abstract
Block copolymers (BCPs) under nanoscale confinement can self-assemble to form novel nanostructures that are not available in the bulk state. Particularly, the ordering process of block copolymers a...
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- 2019
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11. Cascade Self-Organization of Shish Kebabs in Fibers Spun from Polymer Solutions: Crystalline Fibrils Bridging Neighboring Kebabs Discovered by Transmission Electron Microtomography
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Takeji Hashimoto, Takaaki Toriyama, Hiroki Murase, and Hiroshi Jinnai
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chemistry.chemical_classification ,Phase transition ,Bridging (networking) ,Materials science ,Polymers and Plastics ,Organic Chemistry ,macromolecular substances ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Fibril ,Epitaxy ,01 natural sciences ,0104 chemical sciences ,law.invention ,Inorganic Chemistry ,chemistry ,Chemical physics ,law ,Cascade ,Materials Chemistry ,Laplace pressure ,Crystallization ,0210 nano-technology - Abstract
In fibers spun from polymer solutions, we investigated self-organization of ordered shish kebabs via the cascade evolution of various dissipative structures through multistep phase transitions at multiple length scales. We used transmission electron microtomography to discover for the first time crystalline fibrils with diameters of ∼10 nm that orthogonally bridge neighboring kebabs epitaxially overgrown from shishs. The fibrils evolved during the late-stage self-organization processes of the shish kebabs. The fibrils were classified as completely bridging fibrils and pairs of broken fibrils facing each other; the broken fibrils were formed by the following two steps, first by the flow-induced burst of the bridging domains driven by Laplace pressure and subsequent crystallization involved in the burst domains. The bridging and broken fibrils were observed at interkebab distances smaller and larger than the critical length of ∼80 nm, respectively. The bridging fibrils and the cores of the broken fibrils ha...
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- 2019
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12. Stabilizing the Ordered Bicontinuous Double Diamond Structure of Diblock Copolymer by Configurational Regularity
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Takeshi Higuchi, Hiroshi Jinnai, Chih Hsuan Lin, Jing Cherng Tsai, Hsin-Lung Chen, and Takeji Hashimoto
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Materials science ,Polymers and Plastics ,Organic Chemistry ,Diamond ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,Inorganic Chemistry ,Crystal ,Crystallography ,Phase (matter) ,Tacticity ,Metastability ,0103 physical sciences ,Materials Chemistry ,Melting point ,engineering ,Copolymer ,010306 general physics ,0210 nano-technology ,Gyroid - Abstract
We investigate the formation of the ordered bicontinuous structures in a stereoregular diblock copolymer, isotactic polypropylene-block-polystyrene (iPP-b-PS), in which the minority PP block possessed isotactic configuration. This diblock displayed the conventional ordered bicontinuous double gyroid (OBDG) morphology upon heating above the crystal melting point of the iPP block from the as-cast state. The OBDG phase remained stable in the heating process up to the order–disorder transition. In the subsequent cooling process from the nearly disordered state, the OBDG phase first developed, but when the temperature was sufficiently low, an order–order transition from OBDG to the ordered bicontinuous double diamond (OBDD) phase occurred, and OBDD eventually became the dominant structure. The results attested that OBDD and OBDG represented the thermodynamically stable structure at the lower and the higher temperature, respectively, and the OBDG morphology formed in the as-cast state was metastable. The presen...
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- 2018
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13. Direct Characterization of In-Plane Phase Separation in Polystyrene Brush/Cyclohexane System
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Hiroshi Jinnai, Atsushi Takahara, Yuki Norizoe, Yuji Higaki, and Daiki Murakami
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Binodal ,Materials science ,Polymers and Plastics ,Cyclohexane ,Organic Chemistry ,Lipid microdomain ,Analytical chemistry ,Substrate (chemistry) ,Brush ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Upper critical solution temperature ,law ,Phase (matter) ,Polymer chemistry ,Materials Chemistry ,Polystyrene ,0210 nano-technology - Abstract
The phase behavior of polystyrene (PS) brushes in cyclohexane (CHX) was investigated, for the first time, by environmental atomic force microscopy as a function of the graft density and temperature. The polystyrene brushes of three different graft densities exhibited island-, bicontinuous-, and hole-shape microdomains in the direction parallel to the substrate. The size of such “in-plane” microdomains is close to the end-to-end distance of PS brush chain due to the anchoring of one of the chain ends of PS brushes to the substrate. The microdomain structure disappeared as the temperature increased, and new structure with same morphological features reappeared by lowering temperature. This reversible temperature response corresponds to the in-plane phase separation of the PS brush/CHX system. The UCST type binodal line shifted toward slightly lower temperature in the PS brush/CHX system compared to that of the corresponding nongrafted polymer solution, i.e., PS/CHX system, in excellent agreement with our pr...
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- 2016
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14. Yolk/Shell Assembly of Gold Nanoparticles by Size Segregation in Solution
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Kuniharu Ijiro, Takeshi Higuchi, Yoshitaka Bessho, Yasutaka Matsuo, Yoshinori Nishino, Hideyuki Mitomo, Hiroshi Jinnai, Jinjian Wei, Kenichi Niikura, Yasumasa Joti, and Takashi Kimura
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Diffraction ,Chemistry ,Ligand ,Shell (structure) ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Magazine ,Chemical engineering ,law ,Colloidal gold ,0210 nano-technology ,Science, technology and society ,Layer (electronics) ,Ethylene glycol - Abstract
We demonstrate that binary mixtures of small and large gold nanoparticles (GNPs) (5/15, 5/30, 10/30, and 15/30 nm in diameter) in the presence of a glucose-terminated fluorinated oligo(ethylene glycol) ligand can spontaneously form size-segregated assemblies. The outermost layer of the assembly is composed of a single layer of small-sized GNPs, while the larger-sized GNPs are located in the interior, forming what is referred to as a yolk/shell assembly. Time course study reveals that small and large GNPs aggregate together, and these kinetically trapped aggregations were transformed into a size-segregated structure by repeating fusions. A yolk/shell structure was directly visualized in solution by X-ray laser diffraction imaging, indicating that the structure was truly formed in solution, but not through a drying process.
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- 2016
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15. Salt Dependence of the Chain Stiffness and Excluded-Volume Strength for the Polymethacrylate-Type Sulfopropylbetaine in Aqueous NaCl Solutions
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Noboru Ohta, Atsushi Takahara, Motoyasu Kobayashi, Yuki Terayama, Taiki Hoshino, Hiroshi Jinnai, Tatsuya Ishikawa, and Moriya Kikuchi
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Hydrodynamic radius ,Aqueous solution ,Polymers and Plastics ,Chemistry ,Small-angle X-ray scattering ,Intrinsic viscosity ,Organic Chemistry ,Analytical chemistry ,Viscometer ,Polyelectrolyte ,Inorganic Chemistry ,Crystallography ,Virial coefficient ,Materials Chemistry ,Radius of gyration - Abstract
A series of zwitterionic polyelectrolytes poly[3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate] (PMAPS) with a wide range of weight-average molecular weight (Mw) between 5.5 × 103 and 1.6 × 106 g mol–1 with narrow molecular weight distribution (Mw/Mn = 1.07–1.19) were thoroughly characterized in aqueous NaCl solutions for salt concentration (Cs) over a range from theta Cs (0.074 M) to 1.0 M by synchrotron radiation small-angle X-ray scattering (SAXS), light scattering, and viscometry at 25 °C. To determine the chain stiffness parameter (λ–1) and the excluded-volume strength (B) of PMAPS in an aqueous NaCl solution, SAXS profiles and the Mw dependences of the radius of gyration, the second virial coefficient, the interpenetration function, the hydrodynamic radius, and the intrinsic viscosity for PMAPS were analyzed on the basis of the (un)perturbed cylindrical wormlike chain model. The experimental λ–1 value for PMAPS chains in aqueous NaCl solutions barely decreased but was almost consta...
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- 2015
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16. Epitaxial Phase Transition between Double Gyroid and Cylinder Phase in Diblock Copolymer Thin Film
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Hae Woong Park, Junyoung Lee, Hidekazu Sugimori, Taihyun Chang, Hiroshi Jinnai, and Jueun Jung
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Phase transition ,Materials science ,Polymers and Plastics ,Scattering ,Organic Chemistry ,Type (model theory) ,Epitaxy ,Inorganic Chemistry ,Crystallography ,Phase (matter) ,Materials Chemistry ,Grain boundary ,Thin film ,Gyroid - Abstract
The epitaxial relationship in the thermal phase transition between double gyroid (DG) and hexagonally packed cylinder (HEX) phases in polystyrene-block-polyisoprene thin films on Si wafer was investigated using transmission electron microtomography and grazing incidence small-angle X-ray scattering. Two different types of epitaxial transitions were observed, and they appeared to be selectively favored depending on the transition direction. One type of epitaxial relationship prevails in the phase transition from DG to HEX upon heating in which {121}DG, {111}DG, and {220}DG are converted to {100}HEX, {110}HEX, and {001}HEX, respectively. The interphase planes are {220}DG and {001}HEX, and the cylinders meet the {220}DG plane perpendicularly (head-on, Type A) at the grain boundary between DG and HEX. Although there are small dimensional mismatch and distortion in the location of the cylinders in this epitaxial relationship, all cylinders are formed along the topologically equivalent DG skeletal path. On the ...
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- 2014
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17. The Role of Solvent Additive Processing in High Performance Small Molecule Solar Cells
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Kristin Schmidt, Michael L. Chabinyc, Gregory C. Welch, Edward J. Kramer, Michael F. Toney, Hiroshi Jinnai, James Rogers, Alan J. Heeger, Guillermo C. Bazan, Michael A. Brady, Yanming Sun, and Louis A. Perez
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chemistry.chemical_classification ,Fullerene ,Materials science ,General Chemical Engineering ,Energy conversion efficiency ,General Chemistry ,Polymer ,Casting ,Polymer solar cell ,law.invention ,Solvent ,chemistry ,Chemical engineering ,law ,Solar cell ,Materials Chemistry ,Organic chemistry ,Thin film - Abstract
The use of small volumes of a high boiling point liquid as a “solvent additive” is a deposition processing method that has been implemented in most high/record performing polymer:fullerene-based bulk heterojunction (BHJ) solar cell devices. Recently, solvent additive processing has been employed in a solution processable small molecule (SPSM) BHJ system, viz., 5,5′-bis{(4-(7-hexylthiophen-2-yl)thiophen-2-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine}3,3′-di-2-ethylhexylsilylene-2,2′-bithiophene:[6,6]-phenyl C71 butyric acid methyl ester (p-DTS(PTTh2)2:PC71BM), when a small amount, 0.25 v/v %, diiodooctane (DIO) was added to the casting solution, several key device metrics increased, leading to a high power conversion efficiency (PCE) of 6.7%. X-ray diffraction experiments show that the amount of additive added to the casting solution to make p-DTS(PTTh2)2:PC71BM thin films has several effects on the structure at multiple length scales: for example, the number and orientation of p-DTS(PTTh2)2 crystallites, differe...
- Published
- 2014
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18. Liquid Marbles Supported by Monodisperse Poly(methylsilsesquioxane) Particles
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Hiroshi Jinnai, Hirohmi Watanabe, Shigesaburo Ogawa, Atsushi Takahara, Liming Wang, and Thomas J. McCarthy
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Materials science ,Dispersity ,Nanotechnology ,Surfaces and Interfaces ,Substrate (electronics) ,Condensed Matter Physics ,Electrochemistry ,Surface energy ,High surface ,Colloid ,Chemical engineering ,Monolayer ,General Materials Science ,Spectroscopy - Abstract
The preparation of model, well-controlled colloidal assemblies has been a central approach to understanding and optimizing the characteristics and functionality of complex colloidal dispersion systems. This approach, which has created a significant literature and rather deep understanding for emulsions and foams, has yet to be established for the liquid marble (water-in-air) motif. In this article we report the preparation of well-controlled liquid marbles using monodisperse micron-size particles of poly(methylsilsesquioxane) (PMSQ). The low cohesive nature of the stabilizing particles, their narrow size distribution, and their hydrophobicity permit the formation of liquid marbles containing a particulate monolayer with a hexagonally close-packed (HCP) structure. The "cleaning process" by rolling of liquid marbles under a flow of air on a hydrophobic substrate was useful to obtain the monolayer structure. Moreover, the monolayer structure was only obtained from liquids with high surface energy, whereas the others were not useful even though multilayered structure was formed from liquids that have intermediate surface energy.
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- 2014
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19. Robust Liquid Marbles Stabilized with Surface-Modified Halloysite Nanotubes
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Akihisa Takeuchi, Kentaro Uesugi, Atsushi Takahara, Hui Wu, Hirohmi Watanabe, Yoshio Suzuki, Takeshi Higuchi, Aya Fujimoto, Hiroshi Jinnai, and Wei Ma
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Nanotube ,Materials science ,Fabrication ,Nanotubes, Carbon ,Surface Properties ,Inorganic nanotube ,Octadecyltrimethoxysilane ,Nanotechnology ,Surfaces and Interfaces ,engineering.material ,Condensed Matter Physics ,Halloysite ,Surface energy ,chemistry.chemical_compound ,Pincushion ,Chemical engineering ,chemistry ,Agglomerate ,Electrochemistry ,engineering ,General Materials Science ,Particle Size ,Porosity ,Spectroscopy - Abstract
We have demonstrated the fabrication of fluorine-free liquid marbles from halloysite nanotube. Halloysite is a naturally occurring inorganic nanotube that has a high aspect ratio, and the surface was modified with octadecyltrimethoxysilane. The surface-modified halloysite formed pincushion agglomerates on the surface of the liquid droplets, which create superhydrophobic surface similar to that of the plant gall surface prepared by aphids. As a result, the liquid marbles showed high mechanical strength upon impact without the use of low surface energy fluoroalkyl or fluorine-modified materials. Our results suggest a new strategy for designing novel materials for liquid marbles inspired by nature.
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- 2013
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20. Morphological Control of Helical Structures of an ABC-Type Triblock Terpolymer by Distribution Control of a Blending Homopolymer in a Block Copolymer Microdomain
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Takeshi Kaneko, Xi Jiang, Atsushi Takahara, Takeshi Higuchi, Song Hong, Kazuyuki Matsunaga, Volker Abetz, Hiroshi Jinnai, and Hidekazu Sugimori
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Materials science ,Polymers and Plastics ,Distribution control ,Organic Chemistry ,Lipid microdomain ,Transmission Electron Microtomography ,Methacrylate ,Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,Polybutadiene ,chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Polystyrene ,Methyl methacrylate - Abstract
The control of microphase-separated structures in a poly(styrene-block-butadiene-block-methyl methacrylate) (SBM) was investigated in three dimensions by transmission electron microtomography. Neat SBM self-assembled into a double-helical structure of polybutadiene (PB) domains around hexagonally packed core polystyrene (PS) cylinders in a poly(methyl methacrylate) matrix. When PS homopolymer with a lower molecular weight than that of the PS block in SBM was added to the SBM, the PB domains transformed from double-helical structures to spherical domains, while maintaining the helical trajectories. In contrast, adding a higher molecular weight PS to the SBM changed the helical structures from double- to triple-stranded structures and even to four-stranded structures. The helical structures of the PB domains were strongly affected by the distribution of the blended polystyrenes in the core cylindrical PS domains.
- Published
- 2013
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21. Arrangement of Block Copolymer Microdomains Confined inside Hemispherical Cavities
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Gumhye Jeon, Jin Kon Kim, Hiroshi Jinnai, June Huh, and Dusik Bae
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Materials science ,Nanostructure ,Polymers and Plastics ,Organic Chemistry ,Lipid microdomain ,Nanoparticle ,Substrate (electronics) ,Inorganic Chemistry ,chemistry.chemical_compound ,Membrane ,chemistry ,Transmission electron microscopy ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Methyl methacrylate ,Composite material - Abstract
We investigated, via scanning and transmission electron microscopy, the arrangement of the microdomains of symmetric polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) confined in hemispherical cavities. The hemispherical cavities were prepared by using anodic aluminum oxide (AAO) template, where the inner surface of the cavities was modified by thin brush layers of PS, PMMA, and PS-ran-PMMA copolymer. When the inner surface of the cavity is strongly selective to PS chains, concentric rings consisting of PS and PMMA microdomains are formed, replicating the confined geometry of hemisphere. However, as the selectivity of a brush to PS chains becomes weaker, various interesting morphologies are formed that have not been reported in the literature. The experimentally observed microdomain arrangement confined inside the hemispherical cavities was compared with the simulation results based on the dynamic Metropolis Monte Carlo method.
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- 2013
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22. Polymer Janus Particles Containing Block-Copolymer Stabilized Magnetic Nanoparticles
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Masatsugu Shimomura, Hiroshi Yabu, Koji Harano, Hiroshi Jinnai, Masaaki Kanahara, Takeshi Higuchi, Toshihiko Arita, and Eiichi Nakamura
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chemistry.chemical_classification ,Materials science ,Nanoparticle ,Janus particles ,Polymer ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Copolymer ,Magnetic nanoparticles ,General Materials Science ,Polystyrene ,Janus ,Self-assembly ,Composite material - Abstract
In this report, we show a simple route to fabricate Janus particles having magnetic nanoparticles inside them, which can respond and rotate along to magnetic fields. By solvent evaporation from the tetrahydrofran solution of polymer stabilized γ-Fe2O3 nanoparticles, polystyrene (PS), and polyisoprene containing water, aqueous dispersion of Janus microparticles were successfully prepared, and the γ-Fe2O3 nanoparticles were selectively introduced into the PS phase. We demonstrate rotation and accumulation of Janus particles by using a neodymium magnet.
- Published
- 2013
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23. Spreading and Structuring of Water on Superhydrophilic Polyelectrolyte Brush Surfaces
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Atsushi Takahara, Daiki Murakami, Yuka Ikemoto, Motoyasu Kobayashi, Hiroshi Jinnai, and Taro Moriwaki
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Materials science ,Hydrogen bond ,Nanotechnology ,Surfaces and Interfaces ,Condensed Matter Physics ,Electrochemistry ,Polyelectrolyte ,Contact angle ,Chemical engineering ,Superhydrophilicity ,Molecule ,General Materials Science ,Wetting ,Thin film ,Spectroscopy - Abstract
The wetting behavior of superhydrophilic polyelectrolyte brushes was investigated. Reflection interference contrast microscopy demonstrated that the contact angles of water on the polyelectrolyte brushes were extremely low but remained finite in the range of
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- 2013
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24. Influence of Trace Amount of Well-Dispersed Carbon Nanotubes on Structural Development and Tensile Properties of Polypropylene
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Kevin L. White, Atsushi Takahara, Takeshi Higuchi, Peng Liu, Ryohei Ishige, Taiki Hoshino, Hung-Jue Sue, Jiang Xi, Hiroaki Sugiyama, and Hiroshi Jinnai
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Polypropylene ,Solid-state chemistry ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Nucleation ,Slip (materials science) ,Carbon nanotube ,law.invention ,Amorphous solid ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,law ,Ultimate tensile strength ,Materials Chemistry ,Organic chemistry ,Crystallite ,Composite material - Abstract
Functionalized multiwalled carbon nanotubes (F-MWCNTs) were individually dispersed in a commercial polypropylene (PP) matrix using our well-established α-zirconium phosphate (ZrP) nanoplatelet-assisted dispersion approach. The F-MWCNTs remained uniformly dispersed in PP after melt mixing and injection-molding and were found to remarkably enhance modulus and strength at only 0.1 wt % loading. The individual F-MWCNTs were mostly oriented and extended in the flow direction and were shown to be integrated within the crystalline structure of the matrix. The change in mechanical properties is attributed to both the modification in crystal structure due to MWCNT-induced nucleation and the direct reinforcement of crystalline lamellae and amorphous regions by the MWCNTs. We propose that the compatibilized F-MWCNTs exhibit sufficient interfacial interaction with the PP matrix to anchor lamellae stacks and resist interlamellar slip. The F-MWCNTs also reinforce amorphous domains between crystallites and behave as “su...
- Published
- 2013
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25. Tetragonally Perforated Lamellae of Polybutadiene-block-poly(2-vinylpyridine)-block-poly(tert-butyl methacrylate) (BVT) Triblock Terpolymers in the Bulk: Preparation, Cross-Linking, and Dissolution
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Song Hong, Felix H. Schacher, Hiroshi Jinnai, Axel H. E. Müller, and Hidekazu Sugimori
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Solid-state chemistry ,Materials science ,2-Vinylpyridine ,Polymers and Plastics ,Organic Chemistry ,Block (periodic table) ,Methacrylate ,Inorganic Chemistry ,TERT-BUTYL METHACRYLATE ,chemistry.chemical_compound ,Polybutadiene ,chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Dissolution - Abstract
We report on the formation of tetragonally perforated lamellae from a polybutadiene-block-poly(2-vinylpyridine)-block-poly(tert-butyl methacrylate) (BVT) triblock terpolymer, PB22P2VP29PtBMA49110, ...
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- 2012
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26. Gold Nanoparticles Coated with Semi-Fluorinated Oligo(ethylene glycol) Produce Sub-100 nm Nanoparticle Vesicles without Templates
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Takeshi Higuchi, Naoki Fujitani, Naoki Iyo, Hiroshi Jinnai, Kuniharu Ijiro, Takashi Nishio, and Kenichi Niikura
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Butanol ,Vesicle ,technology, industry, and agriculture ,Nanoparticle ,General Chemistry ,Biochemistry ,Catalysis ,Solvent ,chemistry.chemical_compound ,symbols.namesake ,Colloid and Surface Chemistry ,chemistry ,Chemical engineering ,Colloidal gold ,symbols ,Organic chemistry ,Raman spectroscopy ,Ethylene glycol ,Solvophobic - Abstract
Gold nanoparticles (NPs) with diameters of 5, 10, and 20 nm coated with semifluorinated oligo(ethylene glycol) ligands were formed into sub-100 nm hollow NP assemblies (NP vesicles) in THF without the use of a template. The NP vesicles maintained their structure even after the solvent was changed from THF to other solvents such as butanol or CH(2)Cl(2). NMR analyses indicated that the fluorinated ligands are bundled on the NPs and that the solvophobic feature of the fluorinated bundles is the driving force for NP assembly. The formed NP vesicles were surface-enhanced Raman scattering-active capsules.
- Published
- 2012
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27. Solvent-Driven Evolution of Block Copolymer Morphology under 3D Confinement
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Le Li, Kazuyuki Matsunaga, Hiroshi Yabu, Masatsugu Shimomura, Takeshi Higuchi, Thomas P. Russell, Hiroshi Jinnai, Jintao Zhu, and Ryan C. Hayward
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Chloroform ,Materials science ,Polymers and Plastics ,Precipitation (chemistry) ,Annealing (metallurgy) ,Organic Chemistry ,Nanoparticle ,Inorganic Chemistry ,Solvent ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Selectivity ,Tetrahydrofuran - Abstract
Nanoparticles with concentric layered structures were generated from a lamellae-forming poly(styrene-b-isoprene) diblock copolymer using controlled precipitation from a tetrahydrofuran/water mixture. Chloroform, a good solvent for both blocks, was used to swell and anneal the nanoparticles suspended in aqueous media. The three-dimensional morphologies of particles were reconstructed by transmission electron microtomography throughout the process of solvent annealing. A transition from concentric lamellae to PI cylinders in a PS matrix occurred upon annealing, presumably due to a slight selectivity of chloroform for PS. These cylindrical microdomains were further divided into PS-core-PI-shell spherical structures in a PS matrix upon extended annealing, a structure that is unique among reported microphase separated morphologies of diblock copolymers.
- Published
- 2010
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28. Transmission Electron Microtomography and Polymer Nanostructures
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Toshio Nishi, Richard J. Spontak, and Hiroshi Jinnai
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chemistry.chemical_classification ,Nanostructure ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Resolution (electron density) ,Nanotechnology ,Polymer ,Acceleration voltage ,law.invention ,Inorganic Chemistry ,Micrometre ,chemistry ,Transmission electron microscopy ,law ,Materials Chemistry ,Nanometre ,Electron microscope - Abstract
This Perspective summarizes the recent advances and perspective in three-dimensional (3D) imaging techniques and their applications to polymer nanostructures, e.g., microphase-separated structures of block copolymers. We place particular emphasis on the method of transmission electron microtomography (TEMT). As a result of some recent developments in TEMT, it is now possible to obtain truly quantitative 3D images of polymer nanostructures with subnanometer resolution. The introduction of scanning optics in TEMT has made it possible to obtain large volumes of 3D data from a micrometer thick polymer specimens using conventional electron microscopes at relatively low acceleration voltage, 200 kV. Thus, TEMT covers structures over a wide range of thicknesses from a few nanometers to several hundred nanometers, which corresponds to quite an important spatial range for hierarchical polymer nanostructures. TEMT provides clear 3D images and a wide range of new structural information, which cannot be obtained usin...
- Published
- 2010
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29. Cylindrically Confined Diblock Copolymers
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Thomas P. Russell, Priyanka Dobriyal, Hiroshi Jinnai, Hongqi Xiang, Jiun-Tai Chen, and Matsunaga Kazuyuki
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Materials science ,Polymers and Plastics ,Anodizing ,Capillary action ,Organic Chemistry ,Inorganic Chemistry ,Nanopore ,Lamella (surface anatomy) ,Chemical engineering ,Transmission electron microscopy ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Nanorod ,Confined space - Abstract
Lamella-, cylinder-, and sphere-forming block copolymers (BCPs) of polystyrene-b-polybutadiene (PS-b-PBD) were drawn into the pores of anodized aluminum oxide (AAO) membranes in the melt by capillary forces. After thermal annealing, the nanorods of the BCP were removed by dissolution of the AAO with a weak acid, and transmission electron microscopy (TEM) was used to investigate the resultant morphologies of the confined BCPs. The diameters of the pores in the AAO and the molecular weight of the block copolymers were varied to investigate the effect of confinement on the microphase separation of the BCP. Concentric cylinders were observed for the lamella-forming BCPs under 2D confinement, and deviations of the lamella repeat period were measured as a function of AAO pore diameter. In addition, torus-like morphologies were observed as the degree of confinement increased. For the bulk cylinder-forming BCPs, a rich variety of morphologies, not seen in the bulk, were observed that included stacked torus-like m...
- Published
- 2009
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30. A Transition from Cylindrical to Spherical Morphology in Diblock Copolymer Thin Films
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Hiroyasu Masunaga, Hiroshi Morita, Hiroshi Jinnai, Fumio Hirato, Sono Sasaki, Masao Doi, Hidekazu Sugimori, Ken Ichi Niihara, and Ukyo Matsuwaki
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Phase transition ,Materials science ,Morphology (linguistics) ,Polymers and Plastics ,Organic Chemistry ,Substrate (electronics) ,Styrene ,Condensed Matter::Soft Condensed Matter ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Hexagonal lattice ,Composite material ,Thin film ,Phase diagram - Abstract
Microphase-separated structures in poly(styrene-block-isoprene) (SI) block copolymer thin films were investigated by transmission electron microtomography (TEMT). The SI block copolymer showed cylindrical microdomains in the bulk state. Several block copolymer thin films with different thicknesses were prepared by spin-coating and were extensively annealed before the TEMT experiments. Intriguingly, although the cylindrical morphology orienting parallel to the substrate was observed in most of the cases, spherical microdomains were found at certain film thicknesses. The thickness dependence was investigated using a computer simulation based on the self-consistent-field theory, producing a morphological phase diagram based on minimizing free energy. We find that the distortion of the hexagonal lattice of the cylindrical microdomains caused the morphological transition to the spherical microdomains.
- Published
- 2008
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31. Sponge-like Heterogeneous Gels: Hierarchical Structures in Poly(N-isopropylacrylamide) Chemical Gels As Observed by Combined Scattering and Confocal Microscopy Method
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Takeji Hashimoto, Yoshitsugu Hirokawa, Takuya Okamoto, Kazuya Aizawa, Kohtaro Kimishima, Hiroshi Jinnai, and Satoshi Koizumi
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Polymers and Plastics ,Scattering ,Organic Chemistry ,Crystal structure ,Neutron scattering ,Small-angle neutron scattering ,Light scattering ,law.invention ,Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,chemistry ,Chemical engineering ,Confocal microscopy ,law ,Phase (matter) ,Materials Chemistry ,Poly(N-isopropylacrylamide) - Abstract
Internal structures of the opaque poly(N-isopropylacrylamide) gel obtained at the preparation temperature (TP) higher than 24.5 °C was found to have hierarchical structures by means of a combined small-angle-scattering (CSAS) method of small-angle light scattering (SALS), ultra-small-angle neutron scattering (USANS), and small-angle neutron scattering (SANS) with an aid of laser scanning confocal microscopy (LSCM). The combined CSAS and LSCM studies revealed that a global structure of the gels had a sponge-like two-phase structure. The polymer-rich phase of the sponge was filled with microgels having highly cross-linked network (“tight network”) chains that are interconnected by loosely cross-linked network (“loose network”) chains swollen with water, while the other phase of the sponge was mostly composed of water. These two phases were cocontinuous in three-dimensional space, hence, forming macroscopic gels. The SALS and USANS studies clarified that the sponge had a characteristic spacing of ≈12 μm and ...
- Published
- 2008
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32. Nanohole Structure Prepared by a Polystyrene-block-poly(methyl methacrylate)/poly(methyl methacrylate) Mixture Film
- Author
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Wonchul Joo, Hiroshi Jinnai, Seung Yun Yang, and Jin Kon Kim
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Materials science ,Small-angle X-ray scattering ,Mordançage ,Nanoporous ,Surfaces and Interfaces ,Substrate (electronics) ,Condensed Matter Physics ,Poly(methyl methacrylate) ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Etching (microfabrication) ,visual_art ,Polymer chemistry ,Electrochemistry ,visual_art.visual_art_medium ,Copolymer ,General Materials Science ,Methyl methacrylate ,Spectroscopy - Abstract
Cylindrical nanoporous structures were prepared by using a mixture film of polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) and PMMA homopolymer (hPMMA), and they were analyzed by transmission electron microtomography (TEMT), X-ray reflectivity (XR), and grazing incidence small-angle X-ray scattering. For this purpose, the mixture film was spin-coated onto a silicon wafer modified by a neutral brush for PS and PMMA blocks, which generates PMMA cylindrical microdomains oriented normal to the substrate. Two methods were employed to prepare nanoporous structures: (1) all of the PMMA phase (PMMA block and PMMA homopolymer) in the film was removed by UV irradiation, followed by rinsing with a selective solvent (acetic acid) to PMMA and (2) only PMMA homopolymer was removed by selective solvent etching without UV irradiation. We found via TEMT and XR that the nanoporous structure in the film prepared by UV irradiation exhibited almost perfect cylindrical shape throughout the entire film thickness. However, when the film was rinsed with a selective solvent, nanoporous structures were not straight cylinders but had a funnel shape in which the diameter of nanopores located near the top of the film was larger than that located near the bottom of the film.
- Published
- 2008
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33. Three-Dimensional Visualization of a Single Block Copolymer in Lamellar Nanodomains
- Author
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Toshihiro Kawakatsu, Toshio Nishi, Masao Doi, Hiroshi Jinnai, and Hiroshi Morita
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,media_common.quotation_subject ,Organic Chemistry ,Bent molecular geometry ,Frustration ,Polymer ,Radius ,Gyration ,Inorganic Chemistry ,Lamella (surface anatomy) ,chemistry ,Chemical physics ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Lamellar structure ,media_common - Abstract
The single-chain distribution in a poly(styrene-block-isoprene) block copolymer in the bulk state was studied by the combined method of transmission electron microtomography and three-dimensional mesoscale computer simulations. The local frustration of the block chains on a nanoscale can be analyzed using the size of the gyration radius, Rg. Two representative morphologies in the lamellar morphology have been examined, i. e., flat and bent lamellae. The Rg obtained from the proposed new method gave reasonable agreement with the previously measured values. It was shown that the single polymer chains in the bent lamella is more stretched out than those in the flat lamella. This method provides a new insight into understanding the self-assembled structure in the bulk microdomains.
- Published
- 2008
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34. FIB-SEM and TEMT Observation of Highly Elastic Rubbery Material with Nanomatrix Structure
- Author
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Seiichi Kawahara, Yoshimasa Yamamoto, Hideo Nishioka, Ken Ichi Niihara, Hiroshi Jinnai, Yoshinobu Isono, Shuji Fujii, and Akio Takaoka
- Subjects
Inorganic Chemistry ,Materials science ,Nanostructure ,Morphology (linguistics) ,Polymers and Plastics ,Natural rubber ,visual_art ,Organic Chemistry ,Polymer chemistry ,Materials Chemistry ,visual_art.visual_art_medium ,Composite material - Published
- 2008
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35. Observation of the Three-Dimensional Structure of Actin Bundles Formed with Polycations
- Author
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Yoshihito Osada, Hyuck Joon Kwon, Hideo Nishioka, Hidemitsu Furukawa, Akira Kakugo, Hiroshi Jinnai, Kazuhiro Shikinaka, Yoshitaka Aoyama, Jian Ping Gong, and Takaharu Okajima
- Subjects
Morphology (linguistics) ,Polymers and Plastics ,Globular protein ,Bioengineering ,macromolecular substances ,Degree of polymerization ,Chloride ,Biomaterials ,Imaging, Three-Dimensional ,Polymer chemistry ,Polyamines ,Materials Chemistry ,medicine ,Animals ,Actin ,chemistry.chemical_classification ,Molecular Structure ,biology ,Chemistry ,biology.organism_classification ,Polyelectrolytes ,Actina ,Actins ,Polyelectrolyte ,Actin Cytoskeleton ,Pectinidae ,Ionic strength ,Biophysics ,medicine.drug - Abstract
Three-dimensional structures of actin bundles formed with polycations were observed by using transmission electron microtomography and atomic force microscopy. We found, for the first time, that the cross-sectional morphology of actin bundles depends on the polycation species and ionic strength, while it is insensitive to the degree of polymerization and concentration of polycation. Actin bundles formed with poly-N-[3-(dimethylamino)propyl] acrylamide methyl chloride quaternary show a ribbon-like cross-sectional morphology in low salt concentrations that changes to cylindrical cross-sectional morphology with hexagonal packing of the actin filaments in high salt concentrations. Contrastingly, actin bundles formed with poly-L-lysine show triangular cross-sectional morphology with hexagonal packing of the actin filaments. These variations in cross-sectional morphology are discussed in terms of anisotropy in the electrostatic energy barrier.
- Published
- 2007
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36. Unusual Phase Behavior of End-Functionalized Polystyrene-block-poly(n-butyl methacrylate) Copolymer with Maleic Anhydride
- Author
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Dong Hyun Lee, Hiroshi Jinnai, Myung Im Kim, Kazuya Suda, Unyong Jeong, Hye-Jeong Kim, and Jin Kon Kim
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Carboxylic acid ,Transition temperature ,Organic Chemistry ,Maleic anhydride ,Infrared spectroscopy ,Methacrylate ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Transmission electron microscopy ,Phase (matter) ,Polymer chemistry ,Materials Chemistry ,Copolymer - Abstract
The effect of various end-functional groups on the phase behavior of polystyrene-block-poly(n-butyl methacrylate) copolymer (PS-b-PnBMA) was investigated by using small-angle X-ray scattering, conventional and 3-D transmission electron microscopy, rheology, and Fourier-transformed infrared spectroscopy. A PS-b-PnBMA with maleic anhydride (SBM66-MAH) exhibited an unexpected thermoreversible transition occurring at higher temperature than its disorder-to-order transition temperature. The transition was very fast and induced a large increase in shear modulus. However, the transition at higher temperature was not observed in other PS-b-PnBMAs with carboxylic acid, diester, and hydrogen end groups.
- Published
- 2007
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37. A Novel Structural Analysis for a Cylinder-Forming Block Copolymer Thin Film Using Neutron Reflectivity Aided by Transmission Electron Microtomography
- Author
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Keiji Tanaka, Naoya Torikai, Hiroshi Jinnai, Ukyo Matsuwaki, Hironori Atarashi, and Ken Ichi Niihara
- Subjects
Morphology (linguistics) ,Materials science ,Polymers and Plastics ,Scattering ,business.industry ,Organic Chemistry ,Reflectivity ,Inorganic Chemistry ,Optics ,Deuterium ,Materials Chemistry ,Copolymer ,Cylinder ,Neutron ,Thin film ,Composite material ,business - Abstract
Microphase-separated structures of a poly(deuterated styrene-block-2-vinylpyridine) (dPS-b-P2VP) block copolymer in thin films were studied by neutron reflectivity (NR) and transmission electron microtomography (TEMT). The dPS-b-P2VP block copolymer shows a cylindrical morphology in the bulk state. The block copolymer was spun-coated on a Si substrate, which was extensively annealed (170 °C for 14 days) before the NR experiments. The annealed thin film showed a featureless NR profile, the reflectivity monotonically decreased with the increasing scattering vector along the depth direction of the thin film, qz. The portion of the dPS-b-P2VP block copolymer thin film used in the NR experiment was examined by TEMT, from which a three-dimensional (3D) morphology of the block copolymer thin film was successfully obtained. The 3D image clearly showed that the microphase-separated structure inside the thin film had a cylindrical morphology with some order along the depth, but almost no in-plane order. In order to...
- Published
- 2007
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38. Perforated Block Copolymer Vesicles with a Highly Folded Membrane
- Author
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Yongming Chen, Ming Xiong, Jianzhong Du, Hiroshi Jinnai, Hongxia Guo, and Takeshi Kaneko
- Subjects
Inorganic Chemistry ,Membrane ,Polymers and Plastics ,Polymer science ,Vesicle ,Bilayer ,Organic Chemistry ,Perforation (oil well) ,Polymersome ,Materials Chemistry ,Copolymer ,Polymer physics ,Polymeric vesicles - Abstract
Ming Xiong, andHongxia Guo*State Key Laboratory of Polymer Physics and Chemistry,Joint Laboratory of Polymer Science and Materials,Institute of Chemistry, The Chinese Academy of Sciences,Beijing 100080, P. R. ChinaHiroshi Jinnai* and Takeshi KanekoDepartment of Macromolecular Science and Engineering,Graduate School of Science and Engineering,Kyoto Institute of Technology, Goshokaido-cho,Matsugasaki, Kyoto 606-8585, JapanReceiVed February 6, 2007ReVised Manuscript ReceiVed May 14, 2007Closure of block copolymer bilayer in the solution generatesthe so-called polymeric vesicles or polymersomes with thesolvent fills in their internal spaces. Recently, polymeric vesicleshave attracted a great attention not only from academia but alsofrom application field for drug delivery.
- Published
- 2007
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39. Direct Observation of Twisted Grain Boundary in a Block Copolymer Lamellar Nanostructure
- Author
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Toshio Nishi, Koji Sawa, and Hiroshi Jinnai
- Subjects
Surface (mathematics) ,Materials science ,Nanostructure ,Morphology (linguistics) ,Minimal surface ,Polymers and Plastics ,Condensed matter physics ,Organic Chemistry ,Inorganic Chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Grain boundary ,Lamellar structure ,Twist - Abstract
The grain boundary morphology of a lamella-forming poly(styrene-b-isoprene) (SI) diblock copolymer was investigated by transmission electron microtomography. The twist grain boundary, at which two lamellar nanodomains orthogonally intersect, was successfully observed in three dimensions (3D). A two-dimensional periodic minimal surface, the Scherk's first surface, was once hypothesized as a model of such a grain boundary morphology but never experimentally ascertained. The area-averaged curvatures of the interface between the PI and PS nanodomains as well as the interfacial area per unit volume suggested that the grain boundary morphology had characteristics of the saddlelike hyperbolic surface and was found to be quite similar to Scherk's first surface.
- Published
- 2006
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40. Electric Field Alignment of Asymmetric Diblock Copolymer Thin Films
- Author
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Andrei Zvelindovsky, Hiroshi Jinnai, K. S. Lyakhova, Thomas P. Russell, G. J. A. Sevink, and Ting Xu
- Subjects
Phase transition ,Materials science ,Polymers and Plastics ,Condensed matter physics ,business.industry ,Organic Chemistry ,Lipid microdomain ,Neutron scattering ,Quantitative Biology::Subcellular Processes ,Inorganic Chemistry ,Optics ,Transmission electron microscopy ,Electric field ,Materials Chemistry ,Copolymer ,Lamellar structure ,Thin film ,business - Abstract
The electric field alignment of cylindrical microdomains in diblock copolymer thin films was studied using small-angle neutron scattering and transmission electron microscopy. The alignment process was followed with the block copolymer films in different initial states. Starting from a poorly ordered state, the cylindrical microdomain orientation was biased by the surface field that initially drove the cylindrical microdomains to be oriented parallel to the film surface. With further annealing, the cylinders were disrupted locally and formed ellipsoid-shaped microdomains that, with time, connected into cylindrical microdomains oriented in the field direction. Starting from an ordered state with cylinders parallel to the surface, the applied electric field enhanced fluctuations at the interfaces of the microdomains. The growth of the fluctuations continued until the cylindrical microdomains broke up into spherical microdomains, similar to that seen in the thermoreversible cylinder-to-sphere order−order tra...
- Published
- 2005
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41. Dual-Axis Electron Tomography for Three-Dimensional Observations of Polymeric Nanostructures
- Author
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Toshio Nishi, Hiroshi Jinnai, and Hidekazu Sugimori
- Subjects
Materials science ,Nanostructure ,Polymers and Plastics ,business.industry ,Organic Chemistry ,3D reconstruction ,Inorganic Chemistry ,Condensed Matter::Materials Science ,Optics ,Tilt (optics) ,Electron tomography ,Orientation (geometry) ,Materials Chemistry ,Cathode ray ,Tomography ,business ,Anisotropy - Abstract
Transmission electron microtomography (TEMT) has proven to be useful for investigating three-dimensional (3D) nanostructures in polymeric systems. However, the conventional TEMT that uses a tilt series around an axis occasionally fails to reconstruct nanostructures, especially when the nanostructure is highly anisotropic. Namely, if a certain geometrical relationship between orientation of the nanostructure and the tilt axis is fulfilled, the nanostructure does not appear in the 3D reconstruction. This problem can be solved by tilting the specimen around two (orthogonal) tilt axes and combining the resulting two 3D reconstructions after precise alignment between them. The strategy, called “dual-axis tomography”, is used to observe one of the commonly observed anisotropic polymer nanostructures, cylindrical morphology, of poly(styrene-block-isoprene) block copolymer. It was experimentally observed that the cylindrical nanodomains that were “missing” in one of the two tomograms were complementary reconstruc...
- Published
- 2005
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42. Three-Dimensional Observation of Polymer Blend by X-ray Phase Tomography
- Author
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Hiroshi Jinnai, Hidekazu Kadowaki, Akiko Fujii, and Atsushi Momose
- Subjects
Inorganic Chemistry ,Materials science ,Investigation methods ,Polymers and Plastics ,Phase (matter) ,Organic Chemistry ,Polymer chemistry ,Materials Chemistry ,X-ray ,Analytical chemistry ,Polymer blend ,Tomography - Published
- 2005
- Full Text
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43. Nanofibrillar Networks in Poly(ethyl methacrylate) and Its Silica Nanocomposites
- Author
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Richard J. Spontak, David A. Agard, Carol K. Hall, Hiroshi Jinnai, Elizabeth A. Wilder, and Michael B. Braunfeld
- Subjects
chemistry.chemical_classification ,Materials science ,Nanocomposite ,Colloidal silica ,Nanoparticle ,Nanotechnology ,Polymer ,Methacrylate ,Surfaces, Coatings and Films ,chemistry ,Transmission electron microscopy ,Materials Chemistry ,Nanometre ,Physical and Theoretical Chemistry ,Elastic modulus - Abstract
Recent advances in polymer materials design seek to incorporate functionality, enhance existing properties, and reduce weight without compromising mechanical properties or processability. While much attention has been drawn to the development of organic/inorganic hybrid nanocomposites modified with discrete siliceous nanoparticles (such as fumed/colloidal silica or organoclays), other opportunities exist for comparably enlightened materials design. Dibenzylidene sorbitol (DBS) is a sugar derivative that is capable of self-organizing into a 3D nanofibrillar network at relatively low concentrations in a wide variety of organic solvents and polymers. In this work, we explore the morphological characteristics and properties of DBS in poly(ethyl methacrylate) (PEMA) and PEMA nanocomposites with colloidal silica. Transmission electron microscopy and microtomography reveal that the DBS molecules form highly connected networks, with nanofibrils measuring ca. 10 nm in diameter and ranging up to several hundred nanometers in length. Dynamic mechanical property analysis reveals that, while DBS has little effect on glassy PEMA, it serves to increase the elastic modulus in molten PEMA.
- Published
- 2003
- Full Text
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44. Observation of Fine Structure in Bicontinuous Phase-Separated Domains of a Polymer Blend by Laser Scanning Confocal Microscopy
- Author
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Alexander E. Ribbe, Hiroshi Yoshida, Kohtaro Kimishima, Hiroshi Jinnai, Yoshinori Funaki, Yoshitsugu Hirokawa, and Takeji Hashimoto
- Subjects
Length scale ,Materials science ,Polymers and Plastics ,Laser scanning ,Confocal ,Organic Chemistry ,Scanning confocal electron microscopy ,Analytical chemistry ,law.invention ,Inorganic Chemistry ,Polybutadiene ,Chemical engineering ,Confocal microscopy ,law ,Phase (matter) ,Materials Chemistry ,Polymer blend - Abstract
Laser scanning confocal micrographs for blends of poly(styrene-ran-butadiene) (SBR) and polybutadiene (PB) demonstrated the existence of fine structures inside one of the well-characterized macroscopically phase-separated bicontinuous domains, in the depth range of the blends belonging to the bulk. The average size of the fine structures was on the submicrometer length scale, while the characteristic spacing of the macroscopically phase-separated domains was on the order of 10 μm. Fluorescence laser scanning confocal micrographs revealed that the fine structures exist only in the SBR-rich phase. Although the driving force for the formation of the fine structures needs to be investigated further, a small amount of PB molecules in the SBR-rich domains seems to play an important role. Illumination and highlights were shed on the advantage of using laser scanning confocal microscopy for investigation of fine structures in the polymer blends.
- Published
- 2001
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45. Measurements of Interfacial Curvatures of Bicontinuous Structure from Three-Dimensional Digital Images. 2. A Sectioning and Fitting Method
- Author
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Tsuyoshi Koga, Takeji Hashimoto, Hiroshi Jinnai, and Yukihiro Nishikawa
- Subjects
Minimal surface ,Materials science ,business.industry ,Spinodal decomposition ,Gaussian ,Geometry ,Surfaces and Interfaces ,Condensed Matter Physics ,Measure (mathematics) ,Ellipsoid ,Condensed Matter::Soft Condensed Matter ,symbols.namesake ,Optics ,Electrochemistry ,symbols ,General Materials Science ,SPHERES ,Mathematics::Differential Geometry ,Polymer blend ,business ,Spectroscopy ,Gyroid - Abstract
A novel method was developed to measure the local curvatures of phase-separating interface, i.e., the mean and Gaussian curvatures, from three-dimensional (3D) digital images of the bicontinuous domain structures formed during a phase-separation process via spinodal decomposition (SD). One of the aims of the study is to quantify the local geometry of the interface and its time evolution. Distributions of the interfacial curvatures were obtained by calculating the curvatures at many points on the interface. The applicability and precision of the method were critically tested using various model surfaces, e.g., spheres, cylinders, ellipsoids of revolution, and an infinite periodic minimal surface (IPMS), Schoen's gyroid. The method was then applied to the 3D interface developed via SD of a polymer blend. It was found that the interface of the polymer blend (i) was, for the most part, hyperbolic and (ii) had a considerably broader curvature distribution than that of Schoen's gyroid, though area-averaged curv...
- Published
- 2001
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46. Three-Dimensional Structure of a Sintered Macroporous Silica Gel
- Author
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Kazuki Nakanishi, Takeji Hashimoto, Hiroshi Jinnai, Junpei Yamanaka, and Yukihiro Nishikawa
- Subjects
Materials science ,Mean curvature ,Morphology (linguistics) ,Macropore ,Spinodal decomposition ,Silica gel ,Fraction (chemistry) ,Surfaces and Interfaces ,Condensed Matter Physics ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,3d image ,Electrochemistry ,General Materials Science ,Polymer blend ,Spectroscopy - Abstract
Three-dimensional (3D) macroporous morphology of a silica gel, formed as a result of the phase separation parallel to the sol−gel transition, was observed in real space by laser scanning confocal microscopy. The 3D image of the silica gel skeleton that was sintered into full dense pure silica glasses clearly demonstrated that the gel skeleton is continuous and interconnected in 3D space. The interface between the gel skeleton and the macropore was characterized in terms of interfacial curvatures. It was found that a large portion of the interface is hyperbolic, which is also found in a phase-separated structure of a binary polymer mixture developed during the spinodal decomposition (SD). Comparison was made in terms of the probability densities of the interfacial curvatures between the silica gel and a polymer mixture having an identical phase volume fraction to one of the phases. Although the probability density distribution of the mean curvature, H, representing geometrical characteristics of the interf...
- Published
- 2001
- Full Text
- View/download PDF
47. Geometrical Properties and Interface Dynamics: Time Evolution of Spinodal Interface in a Binary Polymer Mixture at the Critical Composition
- Author
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Hidetoshi Morimoto, Yukihiro Nishikawa, Takeji Hashimoto, Hiroshi Jinnai, and Tadanori Koga
- Subjects
Surface (mathematics) ,Spinodal ,Chemistry ,Spinodal decomposition ,Gaussian ,Analytical chemistry ,Time evolution ,Thermodynamics ,Surfaces and Interfaces ,Condensed Matter Physics ,Light scattering ,Condensed Matter::Soft Condensed Matter ,symbols.namesake ,Differential geometry ,Electrochemistry ,symbols ,General Materials Science ,Polymer blend ,Spectroscopy - Abstract
The time-evolution of a three-dimensional (3D), bicontinuous interface of a phase-separated polymer mixture in the late stage spinodal decomposition (SD) process has been studied by laser scanning confocal microscopy (LSCM) and time-resolved light scattering. The time evolution of the interface between two coexisting phases developed via SD (“spinodal interface”) was quantitatively captured in 3D by using LSCM. On the basis of the differential geometry, probability densities of the local curvatures, i.e., the mean and Gaussian curvatures, of the spinodal interface have been experimentally evaluated. We found that a large portion of the interface formed in the late stage SD consists of a saddle-shaped surface, i.e., a hyperbolic surface. The probability densities were used to predict the dynamics of the spinodal interface. Two basic mechanisms are found to be important for the system to reduce interface area during the late stage SD. In addition, the probability densities of the curvatures at various times...
- Published
- 2000
- Full Text
- View/download PDF
48. Direct Observation of Internal Structures in Poly(N-isopropylacrylamide) Chemical Gels
- Author
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Yoshitsugu Hirokawa, Yukihiro Nishikawa, Takuya Okamoto, Takeji Hashimoto, and Hiroshi Jinnai
- Subjects
chemistry.chemical_classification ,Mesoscopic physics ,Polymers and Plastics ,education ,Organic Chemistry ,Direct observation ,Polymer ,law.invention ,Inorganic Chemistry ,chemistry.chemical_compound ,Cross section (physics) ,chemistry ,Chemical engineering ,Confocal microscopy ,law ,Polymer chemistry ,Materials Chemistry ,Poly(N-isopropylacrylamide) ,Confocal laser scanning microscopy - Abstract
Internal structures of translucent poly(N-isopropylacrylamide) gel were for the first time observed by laser scanning confocal microscopy (LSCM). The observed image reflected the mesoscopic internal structures in the gel due to the “fixed concentration fluctuations” of network polymers as described in the text. Three-dimensional internal structures in the gel constructed from a series of the cross section images taken by the LSCM revealed that the gel had a bicontinuous domain structure consisting of regions dense and sparse in polymer networks.
- Published
- 1999
- Full Text
- View/download PDF
49. Control of Self-Assembled Structures in Binary Mixtures of A−B Diblock Copolymer and A−C Diblock Copolymer by Changing the Interaction between B and C Block Chains
- Author
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Kohtaro Kimishima, Takeji Hashimoto, and Hiroshi Jinnai
- Subjects
chemistry.chemical_classification ,Materials science ,Morphology (linguistics) ,Polymers and Plastics ,Scattering ,Organic Chemistry ,Lipid microdomain ,Polymer ,Inorganic Chemistry ,Crystallography ,Natural rubber ,chemistry ,Transmission electron microscopy ,visual_art ,Polymer chemistry ,Materials Chemistry ,visual_art.visual_art_medium ,Copolymer ,Polymer blend - Abstract
Self-assembled structures in solvent-cast mixtures of polystyrene-block-poly(ethylenepropylene) (PS−PEP) and polystyrene-block-(partially hydrogenated polyisoprene) (PS−HPI) were investigated by small-angle X-ray scattering and transmission electron microscopy. Various self-assembled structures were observed in the solution-cast films, depending upon the degree of hydrogenation of the HPI block of the PS−HPI. The microdomain structure of PS domains and domains composed of PEP and HPI (called “rubber domains” hereafter) was first formed at relatively low polymer concentrations during the solvent-casting process over the whole range of the hydrogenation in our experiments. Subsequently, at a higher concentration during the process, phase separation between PEP and HPI in the rubber domains was observed in mixtures with medium and high hydrogenation. For mixtures with low hydrogenation, repulsive interactions between PEP and HPI become large enough to cause the segregation between PEP and HPI, which leads fi...
- Published
- 1999
- Full Text
- View/download PDF
50. Direct Observation of HPL and DG Structure in PS-b-PI Thin Film by Transmission Electron Microscopy
- Author
-
Kyuhyun Im, Hiroshi Jinnai, Taihyun Chang, Moonhor Ree, Bonghoon Chung, Hae Woong Park, and Koji Sawa
- Subjects
Inorganic Chemistry ,Phase transition ,Crystallography ,Morphology (linguistics) ,Polymers and Plastics ,Transmission electron microscopy ,Chemistry ,Organic Chemistry ,Polymer chemistry ,Materials Chemistry ,Direct observation ,Pi ,Thin film - Published
- 2007
- Full Text
- View/download PDF
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