記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Langmuir  

Understanding the aggregation states of polymers at various interfaces, especially buried interfaces, is of pivotal importance not only from an inherent academic interest but also for the design and construction of functional materials and devices. However, precise analysis through laboratory-scale experiments remains challenging. In this study, we focused on X-ray photoelectron spectroscopy combined with a gas cluster ion beam (GCIB/XPS). First, the interfacial width of a polymer bilayer along the normal direction was evaluated using this method and compared with values obtained from neutron reflectivity experiments and theoretical calculations. This makes it clear that GCIB/XPS is well-suited for depth profiling of polymer interfaces at the nanometer scale under appropriate conditions. Building on this information, we applied the method to an epoxy resin adhered to a copper substrate, revealing that amine hardener molecules were segregated at the adhered interface. This study highlights that GCIB/XPS, despite being destructive, is a powerful tool for the structural analysis of buried polymer interfaces, and further advancements in this field are highly anticipated.

DOI： 10.1021/acs.langmuir.5c00911

Web of Science

Scopus

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Langmuir  

Understanding and controlling the surface properties of bioscaffolds are crucial for regulating cell adhesion and proliferation behaviors. We here focused on poly(vinylidene fluoride) (PVDF), in which polymer chains are oriented through poling treatment to form a polar β-form crystal. The surface aggregation states of uniaxially stretched PVDF films subjected to poling treatment were investigated based on water contact angle measurements and sum-frequency generation spectroscopy. During poling treatment under a sufficiently strong electric field, the dipole moments of β-form crystals, which are inherently aligned within each crystalline domain, become more uniformly oriented across the entire film. As a result, the surface resists structural reorganization even upon exposure to water. This stable surface, which maintains its aggregation states despite environmental changes, was found to promote cell adhesion and proliferation, as well as protein adsorption. Our findings contribute to a deeper understanding of the relationship between the aggregation states on polymer scaffold surfaces and protein interactions, ultimately advancing insights into cell behaviors.

DOI： 10.1021/acs.langmuir.5c00334

Web of Science

Scopus

PubMed

掲載種別：研究論文（学術雑誌）   出版者・発行元：Organic Chemistry Frontiers  

We present the oxidative transformation of a corrole isomer, namely, dibenzocorrorin (3), featuring a modified connectivity pattern of bipyrrole moieties within the corrole scaffold, resulting in the formation of pyrrole-embedded polycyclic molecules (1 and 2). The X-ray crystallography analysis of compound 1 revealed the establishment of three C–N bonds through nitrogen sites in the pyrrole and indole rings, leading to a highly π-conjugated core with nine fused aromatic rings. Notably, the β-pyrrole protons of the diazadicyclopentaazulene moiety displayed significant high-field shifts in the 1H-NMR spectrum, attributed to the 12π antiaromatic contribution of the diazadicyclopentaazulene segment, as indicated by NICS and ACID plot analyses. Compound 1 exhibited a broad near-infrared absorption beyond 1000 nm, a narrow electrochemical energy gap (ΔE = 1.15 V), a short excited-state lifetime, and stable photothermal conversion capability. The crystalline packing structure of 1, characterized by staircase-like stacking along the long axis of needle-shaped crystals, facilitated the fabrication of a single-crystal organic field-effect transistor. The resulting device demonstrated p-type semiconductor behaviour, emphasizing the potential of 1 in near-infrared optoelectronic applications.

DOI： 10.1039/d4qo02145b

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Scopus

掲載種別：研究論文（学術雑誌）   出版者・発行元：Polymer Chemistry  

The aggregation states of polymer chains at solid interfaces are strongly related to their adhesion properties. In this study, we focused on sum-frequency generation (SFG) vibrational spectroscopy, which offers the best depth resolution at the sub-nanometer level among available techniques, and explored its potential as an imaging method. A poly(methyl methacrylate) (PMMA) thin film with a line-and-space pattern was prepared on a quartz substrate. Imaging of the interfacial line-and-space structure in the film was successfully achieved based on SFG signals arising from ester methyl groups as well as carbonyl groups. Once SFG imaging was established, it was applied to blend films of polystyrene (PS) and PMMA with different compositions on the quartz substrate, enabling the direct and non-destructive observation of wetting layers and phase-separated structures buried at the substrate interface for the first time. The interfacial adhesion strength between the blend films and the quartz substrate, evaluated using the surface and interfacial cutting analysis system, showed a clear correlation with the interfacial structure of the blend. This study, which enables the analysis of the relationship between the local orientation of polymer chains at the interface and adhesion strength, is expected to contribute greatly to the design of next-generation adhesives and adhesion technologies.

DOI： 10.1039/d4py00951g

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Scopus

掲載種別：研究論文（学術雑誌）   出版者・発行元：Macromolecules  

The surface wettability of polymers can be controlled by van der Waals interactions, which include induction, orientation, and dispersion forces. For most fluoropolymers, the effect of orientation interactions is markedly smaller than the others, particularly in structures with antiparallel packing, where permanent dipoles may cancel each other out. However, poly(vinylidene fluoride) (PVDF), a semicrystalline polymer, exhibits unique piezoelectric properties when its polar β-form crystals are oriented via poling treatment. This study investigates how such orientation influences surface wettability. We demonstrate that the wettability of uniaxially oriented PVDF films changes with poling treatment. Using sum frequency generation spectroscopy and grazing incidence X-ray diffraction measurements, we found that the b-axis of the β-form crystals near the surface aligns perpendicular to the surface under sufficient electric field strength. This alignment facilitates a transition in wettability, which is discussed in terms of dipole interactions near the surface. Our findings contribute to a deeper understanding of the interplay between molecular orientation and surface properties in semicrystalline polymers.

DOI： 10.1021/acs.macromol.4c01925

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Scopus

開催年月日： 2025年7月

会議種別：ポスター発表  

開催年月日： 2025年7月

会議種別：口頭発表（一般）  

開催年月日： 2025年7月

会議種別：口頭発表（一般）  

開催年月日： 2025年7月

開催年月日： 2025年6月 - 2025年7月

会議種別：口頭発表（一般）