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Your search keyword '"Masunaga, Hiroyasu"' showing total 29 results
Start Over Author "Masunaga, Hiroyasu" Journal macromolecules
29 results on '"Masunaga, Hiroyasu"'

2. Crystal Structure and Phase Transition Behavior of Poly(1,2-difluoroethylene)

Author

Yano, Ryouichi, Tashiro, Kohji, Masunaga, Hiroyasu, and Sasaki, Sono

Abstract

For several decades, poly(1,2-difluoroethylene) [PVLF, −(CHFCHF)n−] had been believed to be atacticand amorphous. However, our recent study has revealed that PVLF is an atacticbut partially crystallinepolymer. In the present report, the crystal structure of PVLF, as the most important basic structural information, was determined by the quantitative analysis of 2D wide-angle X-ray diffraction (WAXD) data measured at room temperature. The two chains pass through the orthorhombic unit cell of a= 9.20 Å, b= 5.32 Å, c(chain axis) = 4.97 Å with the space group Pcam. The polymer chains take the deflected zigzag conformation of TS′TS̅′ (torsional angles, T: 180° and S′: 142°), which is contracted slightly from the fully extended all-trans form. The temperature-dependent measurement of the WAXD patterns revealed that the unit cell size increases almost linearly with temperature but shows a small deflection point at around 100 °C. This deflection corresponds to the reversible second-order phase transition between the low-temperature (LT) phase and the high-temperature (HT) phase. The molecular dynamics calculation revealed an occurrence of the thermally activated translational and torsional motion of molecular chains in the HT phase. In parallel, temperature-dependent small-angle X-ray scattering data analysis revealed that the lamellar stacking structure changes irreversibly at the transition point as a result of such thermally enhanced motions of molecular chains.

Published
2024
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5. Effect of the 3-Hydroxyhexanoate Content on Melt-Isothermal Crystallization Behavior of Microbial Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Author

Van Nguyen, Toan, primary, Nagata, Toshiteru, additional, Noso, Kosei, additional, Kaji, Kenshiro, additional, Masunaga, Hiroyasu, additional, Hoshino, Taiki, additional, Hikima, Takaaki, additional, Sakurai, Shinichi, additional, Yamamoto, Kenta, additional, Miura, Yuta, additional, Aoki, Takashi, additional, Yamane, Hideki, additional, and Sasaki, Sono, additional

Published
2021
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6. New Semiconducting Polymers Based on Benzobisthiadiazole Analogues: Tuning of Charge Polarity in Thin Film Transistors via Heteroatom Substitution

Author

Wang, Yang, MASUNAGA, Hiroyasu, Hikima, Yuta, Matsumoto, Hidetoshi, MORI, TAKEHIKO, and Michinobu, Tsuyoshi

Subjects
Organic electronics, chemistry.chemical_classification, Materials science, Polymers and Plastics, Absorption spectroscopy, Organic Chemistry, Inorganic chemistry, Heteroatom, Polymer, Electrochemistry, Acceptor, Inorganic Chemistry, Crystallography, chemistry, Materials Chemistry, Density functional theory, Cyclic voltammetry
Abstract

As one of the most effective molecular design strategies in organic electronics, heteroatom substitution was employed for the first time to study the acceptor variation effects on the optical, electrochemical, molecular assembling, and charge-transport properties of novel semiconducting polymers containing benzobisthiadiazole (BBT)-related heterocycles, namely, poly(dithiazolfluorene-alt-thiadiazolobenzotriazole) (PSN), poly(dithiazolfluorene-alt-selenadiazolobenzotriazole) (PSeN), and poly(dithiazolfluorene-alt-selenadiazolobenzothiadiazole) (PSeS). The effect of the heteroatom substitution was clearly shown in the UV–vis–NIR absorption spectra in which the substitution of the sulfur (S) and/or nitrogen (N) atoms in PSN with the selenium (Se) and sulfur (S) atoms led to a red-shift in the absorption profile. In addition, the energy levels of these polymers, determined from cyclic voltammetry (CV) measurements and density functional theory (DFT) calculations, also varied due to the hetroatom substitution ...

Published
2015

7. Molecular Aggregation States and Physical Properties of Syndiotactic Polystyrene/Hydrogenated Polyisoprene Multiblock Copolymers with Crystalline Hard Domain

Author

Higaki, Yuji, Suzuki, Ken, Kiyoshima, Yudai, Toda, Tomoyuki, Nishiura, Masayoshi, Ohta, Noboru, Masunaga, Hiroyasu, Hou, Zhaomin, and Takahara, Atsushi

Abstract

Molecular aggregation structure and mechanical as well as thermal properties of novel well-defined multiblock copolymers consisting of crystalline syndiotactic polystyrene (sPS) and rubbery hydrogenated polyisoprene (hPIp) were investigated. The morphology and crystalline ordered structure of the multiblock copolymer films prepared by solvent casting from 1,2-dichlorobenzene solution depended on the volume fraction of sPS (VFsPS) and number of blocks. The multiblock copolymer films exhibited ordered morphology with low crystallinity. The crystallinity of the sPS reduced with decreasing the VFsPS. The pentablock copolymer produced more ordered morphology and less crystallinity than the triblock copolymers. The anisotropic orientation and mechanical stability of the δ form sPS crystals in the spherical sPS domains during uniaxial stretching were demonstrated. Tensile testing and dynamic mechanical analysis indicated that these multiblock copolymer films with appropriate sPS fraction are strong, tough, and elastic and thus could be potential candidates for a new type of thermoplastic elastomer with discrete crystalline hard domains.

Published
2024
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9. Hierarchical Structural Change in the Stress-Induced Phase Transition of Poly(tetramethylene terephthalate) As Studied by the Simultaneous Measurement of FTIR Spectra and 2D Synchrotron Undulator WAXD/SAXS Data

Author

Tashiro, Kohji, primary, Yamamoto, Hiroko, additional, Yoshioka, Taiyo, additional, Ninh, Tran Hai, additional, Tasaki, Masafumi, additional, Shimada, Shigeru, additional, Nakatani, Takeshi, additional, Iwamoto, Hiroyuki, additional, Ohta, Noboru, additional, and Masunaga, Hiroyasu, additional

Published
2014
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11. Structural Nanospace Feature and Substrate Contribution to Maintaining Stable Porosity of Polymer Chain in Layer-by-Layer Assembled Isotactic Poly(methyl methacrylate) Films

Author

Ajiro, Hiroharu, primary, Hongo, Chizuru, additional, Maegawa, Masumi, additional, Kamei, Daisuke, additional, Sasaki, Sono, additional, Ogawa, Hiroki, additional, Masunaga, Hiroyasu, additional, Takemoto, Yukie, additional, Horie, Kazuyuki, additional, and Akashi, Mitsuru, additional

Published
2012
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14. Multistep Crystallization Process Involving Sequential Formations of Density Fluctuations, “Intermediate Structures”, and Lamellar Crystallites: Poly(3-hydroxybutyrate) As Investigated by Time-Resolved Synchrotron SAXS and WAXD

Author

Guo, Longhai, primary, Spegazzini, Nicolas, additional, Sato, Harumi, additional, Hashimoto, Takeji, additional, Masunaga, Hiroyasu, additional, Sasaki, Sono, additional, Takata, Masaki, additional, and Ozaki, Yukihiro, additional

Published
2011
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22. New Semiconducting Polymers Based on BenzobisthiadiazoleAnalogues: Tuning of Charge Polarity in Thin Film Transistors viaHeteroatom Substitution.

Author

Wang, Yang, Masunaga, Hiroyasu, Hikima, Takaaki, Matsumoto, Hidetoshi, Mori, Takehiko, and Michinobu, Tsuyoshi

Subjects
*SEMICONDUCTORS, *THIADIAZOLES, *POLARITY (Chemistry), *THIN film transistors, *HETEROCHAIN polymers, *SUBSTITUTION reactions
Abstract

As one of the most effective moleculardesign strategies in organicelectronics, heteroatom substitution was employed for the first timeto study the acceptor variation effects on the optical, electrochemical,molecular assembling, and charge-transport properties of novel semiconductingpolymers containing benzobisthiadiazole (BBT)-related heterocycles,namely, poly(dithiazolfluorene-alt-thiadiazolobenzotriazole)(PSN), poly(dithiazolfluorene-alt-selenadiazolobenzotriazole)(PSeN), and poly(dithiazolfluorene-alt-selenadiazolobenzothiadiazole)(PSeS). The effect of the heteroatom substitution was clearly shownin the UV–vis–NIR absorption spectra in which the substitutionof the sulfur (S) and/or nitrogen (N) atoms in PSN with the selenium(Se) and sulfur (S) atoms led to a red-shift in the absorption profile.In addition, the energy levels of these polymers, determined fromcyclic voltammetry (CV) measurements and density functional theory(DFT) calculations, also varied due to the hetroatom substitutioneffect. Accordingly, thin film transistors (TFTs) based on these polymersshowed different charge transport properties. For example, PSN displayedp-type unipolar performances with a high hole mobilityup to 0.65 cm2V–1s–1. In contrast, PSeS showed n-type dominant charge transport propertieswith an electron mobility up to 0.087 cm2V–1s–1. Intriguingly, PSeN exhibited ambipolar chargetransport properties with balanced μhand μevalues. These different charge polarities in the TFTs werecorrelated to the energy levels, π–π stacking distances,and polymer crystallinities evaluated by their grazing-incidence wide-angleX-ray scattering (GIWAXS) patterns and atomic force microscopy (AFM)images. We believe that this simple and effective approach will guidethe way to developing high-performance ambipolar and/or n-channelsemiconducting polymers for TFTs. [ABSTRACT FROM AUTHOR]

Published
2015
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28. PEDOT Nanocrystal in HighlyConductive PEDOT:PSS PolymerFilms.

Author

Takano, Takumi, Masunaga, Hiroyasu, Fujiwara, Akihiko, Okuzaki, Hidenori, and Sasaki, Takahiko

Subjects
*NANOCRYSTALS, *POLYMER films, *POLYETHYLENE, *X-ray scattering, *CRYSTAL structure, *ELECTRIC conductivity, *CRYSTAL growth
Abstract

The nanometer-size crystallization of poly(3,4-ethylenedioxythiophene)(PEDOT) inside the hydrophobic core region of PEDOT:PSS (PSS: poly(4-styrenesulfonate))in a solid film is found by small and wide-angle X-ray scatteringsusing a synchrotron radiation source. The clarified PEDOT:PSS structureindicates that a nanocrystal of PEDOT surrounded by PSS is grown inthe solid film from randomly oriented PEDOT in a micelle dispersedin water during the course of film fabrication. The addition of ethyleneglycol (EG) to the PEDOT:PSS water dispersion and post-treatment ofthe pristine film with EG both provide similar improvements in PEDOTcrystallinity. The crystallite size of PEDOT increases up to a comparablesize (∼4.8 nm) to the hydrophobic PEDOT core region of themicelle. The electrical conductivity of the solid film is concurrentlyenhanced by 2 orders of magnitude with the growing nanocrystal ofPEDOT. These findings clearly demonstrate the importance of the singlecrystalline PEDOT assisted by EG to obtain high electrical conductivityof the PEDOT:PSS solid film. [ABSTRACT FROM AUTHOR]

Published
2012
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