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田村 由起子*; 荒川 勝利*; 竹中 幹人*; 中西 洋平*; 藤波 想*; 柴田 基樹*; 山本 勝宏*; 宮田 登*; 山田 雅子*; 瀬戸 秀紀*; et al.
Polymer, 333, p.128662_1 - 128662_8, 2025/08
To investigate the relationship between the mechanical properties of silica-filled styrene-butadiene rubber (SBR) and the amount of bound rubber at the filler/rubber interface, the polymer matrix was extracted from silica-filled SBR using toluene at room temperature. In this study, this extraction process was reproduced by leaching a thermally annealed SBR layer deposited on a Si substrate in toluene at room temperature, where the adsorption layer of the SBR was grown at the interface with the substrate by thermal annealing. The SBR adsorption layer on the Si substrate has two-layer structures consisting of an inner and outer adsorption layers, which correspond to the tightly and loosely bound rubbers on the filler surface of the silica-filled SBR, respectively. For the sample annealed for less than 6 h, the outer adsorption layer, loosely bound to the substrate, was easily leached in toluene for 5 min, leaving only the inner adsorption layer on the substrate. For the samples annealed for more than 24 h, a large portion of the outer adsorption layer remained on top of the inner adsorption layer as a terrace structure. However, even for the sample annealed for 24 h, treating with toluene for 24 h completely leached the outer adsorption layer from the inner adsorption layer, although the inner adsorption layer remained on the substrate. It was found that the loosely bound rubber in the silica-filled SBR could be easily extracted from the filler surface, along with the free polymer chains in the polymer matrix during extraction with toluene at room temperature. In contrast, the tightly bound rubber was not leached by toluene at room temperature. This may be because the interfacial polymer chains within approximately 1 nm of the substrate surface were strongly constrained to the substrate, and even toluene molecules were excluded.
山本 勝宏*; 今井 達也*; 河合 純希*; 伊藤 恵利*; 宮崎 司*; 宮田 登*; 山田 悟史*; 瀬戸 秀紀*; 青木 裕之
ACS Applied Materials & Interfaces, 16(48), p.66782 - 66791, 2024/11
被引用回数:0 パーセンタイル:0.00(Nanoscience & Nanotechnology)In this study, a silicon-based copolymer, poly(tris(trimethylsiloxy)-3-methacryloxypropylsilane)-co-poly(N,N-dimethyl acrylamide), thin film was subjected to plasma surface treatment to make its surface hydrophilic (biocompatible). Neutron reflectivity (NR) measurement of the plasma-treated thin film showed a decrease in the film thickness (etching width: similar to 20 nm) and an increase in the scattering length density (SLD) near the surface (similar to 15 nm). The region with a considerably high SLD adsorbed water (DO) from its saturated vapor, indicating its superior surface hydrophilicity. Nevertheless of the hydrophilicity, the swelling of the thin film was suppressed. Hard X-ray photoelectron spectroscopy (HAXPES) performed at various takeoff angles revealed that the thin-film surface (similar to 20 nm depth) underwent extensive oxidation. NR and HAXPES analysis quantitatively yielded the depth profiling of elemental compositions in a few tens of nm scale. Si oxidation and hydrogen elimination (probably CH
groups) in the vicinity of the surface region increased the SLD and decreased the hydrophobicity. A combination of Soft X-ray photoelectron spectroscopy and NR measurements revealed the surface chemical composition and mass density. It was considered that the surface near the film was chemically composed close to SiO
, forming a gel-like (three-dimensional network) structure that is hydrophilic and suppresses swelling due to moisture, indicating it can be expected to maintain stable hydrophilicity on the film surface.
宮崎 司*; 宮田 登*; 有馬 寛*; 下北 啓輔*; 山本 勝宏*; 竹中 幹人*; 中西 洋平*; 柴田 基樹*; 青木 裕之; 山田 悟史*; et al.
Colloids and Surfaces A; Physicochemical and Engineering Aspects, 701, p.134928_1 - 134928_8, 2024/11
被引用回数:0 パーセンタイル:0.00(Chemistry, Physical)Isotactic polypropylene (PP) thin films deposited on Si substrates were subjected to neutron reflectivity (NR) measurements under various humidity conditions to evaluate the isothermal adsorption of water accumulated between the PP layer and Si substrate, with focus on the temperature-dependence of the adsorption isotherm. The adsorption of accumulated water followed a single type II isotherm according to the Brunauer-Emmett-Teller (BET) classification, regardless of temperature. This can be attributed to the weak interactions between the PP layer and Si substrate, and between the PP layer and water molecules. Hydrophobic PP does not significantly interact with water molecules and the hydrophilic Si surface. Therefore, the interfacial water molecules are simply adsorbed on the native oxide layer on Si via simple interaction between the water molecules and the silicon oxide surface without being affected by the PP layer. Consequently, the adsorption isotherm of the accumulated water follows the single type II adsorption isotherm regardless of temperature, similar to the adsorption isotherm of water simply adsorbed on exposed silica surfaces. These weak interactions of the PP layer with the Si surface and water molecules also lead to fast diffusion kinetics for the accumulated water along the interface.
下北 啓輔*; 山本 勝宏*; 宮田 登*; 柴田 基樹*; 中西 洋平*; 荒川 勝利*; 竹中 幹人*; 木田 拓充*; 徳満 勝久*; 田中 亮*; et al.
Langmuir, 40(30), p.15758 - 15766, 2024/07
被引用回数:0 パーセンタイル:0.00(Chemistry, Multidisciplinary)To investigate the structure of the interface between polyethylene films and substrates, the neutron reflectivity (NR) of deuterated polyethylene (dPE) thin films deposited on Si substrates was measured, demonstrating water accumulation at the interface, even under ambient conditions. After leaching the thermally annealed dPE films in hot p-xylene, NR measurements were conducted on the layers remaining on the substrate, clearly revealing that the adsorption layer of dPE grew during annealing and consisted of two layers, an inner adsorption layer and an outer adsorption layer, as previously proposed for amorphous polymers. The inner adsorption layer was approximately 3.7 nm thick with a density comparable to that of the bulk. The outer adsorption layer was several nanometers thick and appeared to grow insufficiently on top of the inner adsorption layer under the annealing conditions examined in this study. This study clarifying the growth of the adsorption layer of polyethylene at the interface with an inorganic substrate is useful for improving the performance of polymer/inorganic filler nanocomposites due to the wide utility of crystalline polyolefins as polymer matrix materials in nanocomposites.
辻 勇人*; 中畑 雅樹*; 菱田 真史*; 瀬戸 秀紀*; 元川 竜平; 井上 大傑*; 江川 泰暢*
Journal of Physical Chemistry Letters (Internet), 14(49), p.11235 - 11241, 2023/12
被引用回数:6 パーセンタイル:63.96(Chemistry, Physical)This work investigates the water-fraction dependence of the aggregation behavior of hydrophobic solutes in water-tetrahydrofuran (THF) and the elucidation of the role of THF using fluorescence microscopy, dynamic light scattering, neutron and X-ray scattering, as well as photoluminescence measurements. Based on the obtained results, the following model is proposed: hydrophobic molecules are molecularly dispersed in the low-water-content region (10-20 vol %), while they form mesoscopic particles upon increasing the water fraction to 30 vol percent. This abrupt change is due to the composition fluctuation of the water-THF binary system to form hydrophobic areas in THF, followed by THF-rich droplets where hydrophobic solutes are incorporated and form loose aggregates. Further increasing the water content prompts the desolvation of THF, which decreases the particle size and generates tight aggregates of solute molecules. This model is consistent with the luminescence behavior of the solutes and will be helpful to control the aggregation state of hydrophobic solutes in various applications.
下北 啓輔*; 山本 勝宏*; 宮田 登*; 中西 洋平*; 柴田 基樹*; 竹中 幹人*; 山田 悟史*; 瀬戸 秀紀*; 青木 裕之; 宮崎 司*
Soft Matter, 19(11), p.2082 - 2089, 2023/03
被引用回数:3 パーセンタイル:52.54(Chemistry, Physical)In the case of poly(methyl methacrylate) (PMMA) thin films on a Si substrate, thermal annealing induces the formation of a layer of PMMA chains tightly adsorbed near the substrate interface, and the strongly adsorbed PMMA remains on the substrate, even after washing with toluene (hereinafter called adsorbed sample). Neutron reflectometry revealed that the concerned structure consists of three layers: an inner layer (tightly bound on the substrate), a middle layer (bulk-like), and an outer layer (surface) in the adsorbed sample. When an adsorbed sample was exposed to toluene vapor, it became clear that, between the solid adsorption layer (which does not swell) and bulk-like swollen layer, there was a "buffer layer" that could sorb more toluene molecules than the bulk-like layer. This buffer layer was found not only in the adsorbed sample but also in the standard spin-cast PMMA thin films on the substrate. When the polymer chains were firmly adsorbed and immobilized on the Si substrate, the freedom of the possible structure right next to the tightly bound layer was reduced, which restricted the relaxation of the conformation of the polymer chain strongly. The "buffer layer" was manifested by the sorption of toluene with different scattering length density contrasts.
下北 啓輔*; 山本 勝宏*; 宮田 登*; 有馬 寛*; 中西 洋平*; 竹中 幹人*; 柴田 基樹*; 山田 悟史*; 瀬戸 秀紀*; 青木 裕之; et al.
Langmuir, 38(41), p.12457 - 12465, 2022/10
被引用回数:2 パーセンタイル:13.50(Chemistry, Multidisciplinary)We measured the neutron reflectivity (NR) of isotactic polypropylene (PP) thin films deposited on Si substrates modified by hexamethyldisilazane (HMDS) at the saturated vapor pressure of deuterated water at 25C and 60
C/85% RH to investigate the effect of HMDS on the interfacial water accumulation in PP-based polymer/inorganic filler nanocomposites and metal/resin bonding materials. We found that the amount of water accumulated at the PP/Si interface decreased with increasing immersion time of the Si substrate in a solution of HMDS in hexane prior to PP film deposition. During the immersion of the Si substrate, the HMDS molecules were deposited on the Si substrate as a monolayer without aggregation. Furthermore, the coverage of the HMDS monolayer on the Si substrate increased with increasing immersion time. At 60
C and 85% RH, only a slight amount of interfacial water was detected after HMDS treatment for 1200 min. As a result, the maximum concentration of interfacial water was reduced to 0.1 from 0.3, where the latter corresponds to the PP film deposited on the untreated substrate.
根本 文也*; 山田 悟史*; 日野 正裕*; 青木 裕之; 瀬戸 秀紀*
Soft Matter, 18(3), p.545 - 553, 2022/01
被引用回数:3 パーセンタイル:31.02(Chemistry, Physical)Surface aligning agents, such as amphiphilic surfactants, are widely used to control the initial alignment of nematic liquid crystals (NLCs) in liquid crystal displays (LCDs). Generally, these agents are first coated on a substrate prior to NLC introduction. When mixed with NLCs, long alkyl chain amphiphilic agent additives may control the NLC alignment without requiring pretreatment because they may spontaneously form an adsorbed layer at the solid-NLC interface. These self-assembled layers (SALs) appear promising in the effective control of the initial alignment of LCDs. However, direct observation of the adsorbed layer structure in contact with the NLCs is challenging due to probe limitations. Furthermore, the areal densities and alignments of the amphiphiles adsorbed from NLCs at the solid-NLC interface are not previously reported. Herein, the structure of the surface aligning agent -hexadecyltrimethylammonium-d
bromide (d-CTAB) was investigated at the silicon-NLC interface using
neutron reflectometry (NR), which indicated that the CTAB self-assembled as a monolayer, with its alignment dependent on the amphiphile concentration. At low amphiphile concentrations, the alignment of the SAL and NLCs was parallel to the substrate. With increasing amphiphile concentration, the number of amphiphiles attached to the substrate increased within the framework of the Gibbs monolayer, with the alignment of the amphiphiles and NLCs becoming perpendicular to the substrate. The experimental setup used here is comparable to those of more natural systems, such as those found in the alignment of NLCs in LCDs.
Kumar, S.*; Saha, D.*; 高田 慎一; Aswal, V. K.*; 瀬戸 秀紀
Applied Physics Letters, 118(15), p.153701_1 - 153701_7, 2021/04
被引用回数:8 パーセンタイル:47.11(Physics, Applied)We report the pathways to suppress or enhance the protein adsorption on nanoparticles and thereby control the stability of the nanoparticle-protein complexes with the help of selective additives. This has been achieved by tuning the electrostatic interaction between the nanoparticles and proteins, in the presence of surfactant and multivalent counterions. The preferential binding of the proteins with the surfactant and multivalent ions induced charge reversibility of nanoparticles can lead to adsorption of an otherwise non-adsorbing protein and vice versa. The findings are demonstrated for anionic silica nanoparticles and two globular proteins [lysozyme (cationic) and bovine serum albumin (BSA) (anionic)] as model systems, in the presence of two ionic surfactants [anionic sodium dodecyl sulfate (SDS) and cationic dodecyltrimethylammonium bromide (DTAB)], and ZrCl as multivalent salt.
Singh, H.*; Ray, D.*; Kumar, S.*; 高田 慎一; Aswal, V. K.*; 瀬戸 秀紀
Physical Review E, 102(6), p.062601_1 - 062601_11, 2020/12
被引用回数:13 パーセンタイル:71.10(Physics, Fluids & Plasmas)The interaction of nanoparticles with surfactants is extensively used in a wide range of applications from enhancing colloidal stability to phase separation processes as well as in the synthesis of noble functional materials. The interaction is highly specific depending on the charged nature of the surfactant. In the case of nonionic surfactants, the micelles adsorb on the surface of nanoparticles. The adsorption of nonionic surfactant C12E10 as a function of surfactant concentration for two different sizes of anionic silica nanoparticles (16 and 27 nm) has been examined using dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The study on different-sized nanoparticles shows that the lower curvature enhances the packing fraction whereas the loss of surface-to-volume ratio suppresses the fraction of adsorbed micelles with the increase in the nanoparticle size.
梶本 亮一; 横尾 哲也*; 中村 充孝; 川北 至信; 松浦 直人*; 遠藤 仁*; 瀬戸 秀紀*; 伊藤 晋一*; 中島 健次; 河村 聖子
Physica B; Condensed Matter, 562, p.148 - 154, 2019/06
被引用回数:17 パーセンタイル:58.46(Physics, Condensed Matter)Seven time-of-flight quasielastic/inelastic neutron scattering instruments are installed on six beamlines in the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC). Four of these instruments are chopper-type direct-geometry spectrometers, one is a near-backscattering indirect-geometry spectrometer, and the other two are spin-echo-type spectrometers. This paper reviews the characteristic features, recent scientific outcomes, and progress in development of MLF spectrometers.
瀬戸 秀紀; 伊藤 晋一; 横尾 哲也*; 遠藤 仁*; 中島 健次; 柴田 薫; 梶本 亮一; 河村 聖子; 中村 充孝; 川北 至信; et al.
Biochimica et Biophysica Acta; General Subjects, 1861(1), p.3651 - 3660, 2017/01
被引用回数:39 パーセンタイル:82.18(Biochemistry & Molecular Biology)1MWクラスのパルス中性子源であるJ-PARCの物質・生命科学実験施設には、23の中性子ビームラインがあり、21台の装置が稼働、建設中である。このうち6台は中性子非弾性、及び、準弾性実験のための装置であり、生命科学研究に大いに寄与するものである。
Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07
被引用回数:33 パーセンタイル:75.28(Astronomy & Astrophysics)重心エネルギー200GeVでの縦偏極陽子陽子衝突からのジェット生成のイベント構造と二重非対称()について報告する。光子と荷電粒子がPHENIX実験で測定され、イベント構造がPHYTIAイベント生成コードの結果と比較された。再構成されたジェットの生成率は2次までの摂動QCDの計算で十分再現される。測定された
は、一番低い横運動量で-0.0014
0.0037、一番高い横運動量で-0.0181
0.0282であった。この
の結果を幾つかの
の分布を仮定した理論予想と比較する。
Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; 秋葉 康之*; Al-Bataineh, H.*; Alexander, J.*; 青木 和也*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
被引用回数:192 パーセンタイル:99.39(Physics, Nuclear)200GeVと62.4GeVでの陽子陽子の中心衝突からのの横運動量分布及び収量をRHICのPHENIX実験によって測定した。それぞれエネルギーでの逆スロープパラメーター、平均横運動量及び単位rapidityあたりの収量を求め、異なるエネルギーでの他の測定結果と比較する。また
や
スケーリングのようなスケーリングについて示して陽子陽子衝突における粒子生成メカニズムについて議論する。さらに測定したスペクトルを二次の摂動QCDの計算と比較する。
Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; 秋葉 康之*; Al-Bataineh, H.*; Alexander, J.*; 青木 和也*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
被引用回数:10 パーセンタイル:54.72(Physics, Nuclear)重いフレーバーのメソンの崩壊からの電子の測定は、このメソンの収量が金金衝突では陽子陽子に比べて抑制されていることを示している。われわれはこの研究をさらに進めて二つの粒子の相関、つまり重いフレーバーメソンの崩壊からの電子と、もう一つの重いフレーバーメソンあるいはジェットの破片からの荷電ハドロン、の相関を調べた。この測定は重いクォークとクォークグルオン物質の相互作用についてのより詳しい情報を与えるものである。われわれは特に金金衝突では陽子陽子に比べて反対側のジェットの形と収量が変化していることを見いだした。
Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03
被引用回数:181 パーセンタイル:98.31(Astronomy & Astrophysics)RHIC-PHENIX実験で重心エネルギー200GeVの陽子陽子衝突からの,
,
と
中間子生成の微分断面積を測定した。これらハドロンの横運動量分布のスペクトルの形はたった二つのパラメーター、
、のTsallis分布関数でよく記述できる。これらのパラメーターはそれぞれ高い横運動量と低い横運動量の領域のスペクトルを決めている。これらの分布をフィットして得られた積分された不変断面積はこれまで測定されたデータ及び統計モデルの予言と一致している。
金谷 利治*; 高橋 伸明; 西田 幸次*; 瀬戸 秀樹*; 長尾 道弘*; 武田 隆義*
Physica B; Condensed Matter, 385-386(1), p.676 - 681, 2006/11
被引用回数:13 パーセンタイル:50.83(Physics, Condensed Matter)中性子スピンエコー法により三種類のポリビニルアルコール(PVA)ゲルについて研究した。第一にジメチルスルホキシド(DMSO)と水を体積混合比60対40で混合したものを溶媒とするもの、第二にPVAのホウ酸水溶液、そして第三に化学架橋のPVAゲルである。中間散乱関数I(q,t)/I(q,0)はそれぞれ大きく異なった。最初のゲルと第三のゲルは、非減衰項を含むが、第二のゲルは含まなかった。これは非減衰項が静的濃度揺らぎに起因して起こることを示唆している。静的濃度揺らぎと動的濃度揺らぎはそれぞれ、ゲル網目による運動の制限とZimmモードに起因する高分子鎖セグメントの運動を示していることが明らかとなった。
梶本 亮一; 中村 充孝; 柴田 薫; 山田 武*; 遠藤 仁*; 伊藤 晋一*; 横尾 哲也*; 中島 健次; 河村 聖子; 川北 至信; et al.
no journal, ,
MLF has 6 inelastic neutron scattering and quasi-elastic neutron scattering instruments in MLF. 4SEASONS and HRC are Fermi chopper type direct geometry spectrometers, and AMATERAS is one of a disk chopper type. POLANO is a chopper spectrometer capable to use polarized neutron. DNA is a near-back scattering spectrometer with a pulse-shaping chopper, and available to measure at eV resolution. Neutron spin echo spectrometer VIN ROSE includes 2 instruments, MIEZE type and NRSE type. With these instruments, MLF gives opportunities to perform experiments in widely spread fields including solid state physics, amorphous materials and liquids, soft and biological matters, as well as industrial applications such as tire rubbers and battery materials. In this presentation, we review the characteristic features of these 6 instruments and scientific opportunities realized by the instruments.
梶本 亮一; 横尾 哲也*; 中村 充孝; 柴田 薫; 川北 至信; 松浦 直人*; 遠藤 仁*; 瀬戸 秀紀*; 伊藤 晋一*; 中島 健次; et al.
no journal, ,
Materials and Life Science Experimental Facility (MLF) in J-PARC has 23 neutron beam ports, and 21 instruments have already been operated or under construction/commissioning. There are 6 instruments for inelastic neutron scattering and quasi-elastic neutron scattering. By a combination of these instruments, MLF gives opportunities to perform experiments in widely spread fields including solid state physics, amorphous materials and liquids, soft and biological matters, as well as industrial applications such as tire rubbers and battery materials. In this presentation, we review the characteristic features of these 6 instruments and scientific opportunities realized by the instruments.
梶本 亮一; 横尾 哲也*; 中村 充孝; 川北 至信; 松浦 直人*; 遠藤 仁*; 瀬戸 秀紀*; 伊藤 晋一*; 中島 健次; 河村 聖子
no journal, ,
J-PARC・MLFには6ビームライン・7台の非弾性・準弾性装置が設置され、物質中の原子・スピンのダイナミクスの研究に供されている。サブmeV以上のエネルギー領域は4台の直接配置型分光器HRC,アマテラス,四季,POLANOが担っている。HRCは高エネルギー・高分解能の測定が可能なフェルミチョッパー分光器、アマテラスは冷中性子に最適化されたディスクチョッパー分光器、四季は分解能は控えめながら高強度・高測定効率を目指したFermiチョッパー分光器である。POLANOは上記3台にはない中性子偏極解析オプションを備えるFermiチョッパー分光器である。一方、より低エネルギー側を担う装置がDNAとVIN ROSEである。逆転配置型分光器DNAは背面反射配置の結晶アナライザーによりeV
meV領域の実験が可能である。MIEZE型とNRSE型の2台からなる中性子共鳴スピンエコー分光器群VIN ROSEはサブ
eVまでもの低いエネルギー領域をカバーする。このようにMLFの中性子分光器群は互いに補完する関係にあり、合わせて10
meVから10
meVまでの広いエネルギースケールの研究を可能としている。その研究対象は超伝導体、量子スピン系、エネルギー材料、非晶質材料、液体、ソフトマター、生体物質等、多岐にわたる。本発表では各装置の主な仕様、最近の整備・高度化および研究成果について総覧する。