Papers - Oaki, Yuya

結晶を活用した高分子の形の制御

OAKI Yuya

高分子 66   221 - 222 2017.05

Accepted

Visualization and Quantitative Detection of Friction Force by Self-Organized Organic Layered Composites

H.Terada, H.Imai, Y.Oaki

Advanced Materials (Advanced Materials)  30 ( 27 )  2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  09359648

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Visualization and quantitative detection of external stimuli are significant challenges in materials science. Quantitative detection of friction force, a mechanical stress, is not easily achieved using conventional stimuli-responsive materials. Here, the quantitative detection of friction force is reported, such as the strength and accumulated ammount, from the visible color of organic layered composites consisting of polydiacetylene (PDA) and organic amines without an excitation light source. The composites of the layered diacetylene monomer crystal and interlayer organic amine are synthesized through self-organization from the precursor solution. After topochemical polymerization, the layered composites based on PDA show tunable temperature-responsive and mechanoresponsive color-change properties depending on the types of interlayer amines. The layered composites are homogeneously coated on a filter paper. The change in color of the paper is quantitatively used to visualize the strength and accumulated amount of the applied friction force. Furthermore, writing pressure is measured by friction force using the paper device.

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Emergence of temperature-dependent and reversible color-change properties by stabilization of layeredpolydiacetylene through intercalation

Y. Oaki, Y. Ishijima, H. Imai

Polymer Journal (Polymer Journal)  50 ( 4 ) 244 - 247 2018.01

Research paper (scientific journal), Joint Work, Accepted,  ISSN  00323896

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The stimuli-responsive color-changing properties of functional polymers are applied to the development of sensing and imaging devices. Tuning the stimuli responsivity is required for a wide range of applications. Polydiacetylene (PDA) derivatives show color changes with the application of external stimuli, such as heat and mechanical stress. Our group has focused on the layered crystal structure of PDA and its intercalation chemistry. The original layered PDA shows an irreversible color transition from blue to red upon heating to the threshold temperature. Here, we found that alkyldiamine-intercalated PDA possessed different color-changing properties, such as a higher color transition temperature and a temperature-dependent and reversible color change, than the original PDA. As the alkyl-chain length increased, the color-changing behavior gradually converted from the irreversible color transition type to the reversible temperature-dependent one. Since the intercalated diamine had a stabilizing effect on the layered structure, the stimuli responsivity varied according to the type of diamine. The results suggest that the stimuli-responsive color-changing properties of layered PDA can be finely and systematically tuned by the intercalation of organic guests.

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Few-layered titanate nanosheets with large lateral size and surface functionalization: Potentials for controlled exfoliation of inorganic-organic layered composite

G. Nakada、H. Imai, Y. Oaki

Chemical Communications (Chemical Communications)  54 ( 3 ) 244 - 247 2018.01

Research paper (scientific journal), Joint Work, Accepted,  ISSN  13597345

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Herein, few-layered titanate nanosheets with a large lateral size and surface functionalization were synthesized via the exfoliation of precursor layered composites in an organic medium. The combination of layered compounds, intercalated guests, and dispersion media has the potential for the synthesis of nanosheets with controlled lateral sizes, thicknesses, and surface chemistry through exfoliation.

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Effects of intercalation rate on layered crystal structures and stimuli-responsive color-change properties of polydiacetylene

M. Takeuchi, H. Imai, Y. Oaki

Journal of Materials Chemistry C 5 ( 32 ) 8250 - 8255 2017.07

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2050-7526

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Tunable Mechano-responsive Color-Change Properties of Organic Layered Material by Intercalation

Y. Ishijima, H. Imai, Y. Oaki

Chem 3   509 - 521 2017.05

Research paper (scientific journal), Joint Work, Accepted

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Hierarchical bicontinuous structure of redox-active organic composites and their enhanced electrochemical properties

K. Sato, M. Arayasu, H. Masaki, H. Imai, Y. Oaki

Chemical Communications 53 ( 53 ) 7329 - 7332 2017.05

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1359-7345

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Real-Time Imaging of 2D and 3D Temperature Distribution: Coating of Metal-Ion-Intercalated Organic Layered Composites with Tunable Stimuli-Responsive Properties

M. Takeuchi, H. Imai, Y. Oaki

ACS Applied Materials and Interfaces 9 ( 19 ) 16546 - 16552 2017.04

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1944-8244

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Multistage Redox Reaction of Conductive-Polymer Nanostructures with Lithium Ion: Potentials for High-Performance Organic Anode

H.Numazawa, K.Sato, H.Imai, Y.Oaki

NPG Asia Materials  2018

Research paper (scientific journal), Joint Work, Accepted

Two exfoliation approaches for organic layered compounds: hydrophilic and hydrophobic polydiacetylene nanosheets

Y. Ishijima, M. Okaniwa, Y. Oaki, Hiroaki Imai

Chemical Science 8 ( 1 ) 647 - 653 2017.04

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2041-6520

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Phase separation through simultaneous polymerization and crystallization for composite materials

K. Sato, Y. Oaki, H. Imai

NPG Asia Materials 9   e377 2017.04

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1884-4049

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Coupled Exfoliation and Surface Functionalization of Titanate Monolayer for Bandgap Engineering

Y. Yamamoto, Y. Oaki, H. Imai

Advanced Materials Interface 4 ( 7 ) 1601014 2017.03

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2196-7350

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Conductive Polymer Nanosheets Generated from the Crystal Surface of Organic Oxidant

K. Sato, H. Masaki, M. Arayasu, Y. Oaki, H. Imai

ChemPlusChem 82 ( 2 ) 177 - 180 2017.02

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2192-6506

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Morphology Design of Crystalline and Polymer Materials from Nanoscopic to Macroscopic Scales

OAKI Yuya

Bulletin of the Chemical Society of Japan 90 ( 7 ) 776 - 788 2017.07

Single Work, Accepted,  ISSN  0009-2673

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Tunable photochemical properties of a covalently anchored and spatially confined organic polymer in a layered compound

H. Matsui, Y. Oaki, H. Imai

Nanoscale 8 ( 21 ) 11076 - 11083 2016

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2040-3364

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Surface-functionalized hydrophilic monolayer of titanate and its application to dopamine detection

H. Matsui, Y. Oaki, H. Imai

Chemical Communications 52   9466 - 9469 2016

Research paper (scientific journal), Joint Work, Accepted

Intercalation-Induced Tunable Stimuli-Responsive Color-Change Properties of Crystalline Organic Layered Compound

M. Okaniwa, Y. Oaki, H. Imai

Advanced Functional Materials 26 ( 20 ) 3463 - 3471 2016

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1616-301X

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Crystal-surface-induced simultaneous synthesis and hierarchical morphogenesis of conductive polymers

K. Kuwabara, Y. Oaki, H. Imai

Chemical Communications 51 ( 47 ) 9698 - 9701 2015

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1359-7345

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Hydrophobic monolayered nanoflakes of tungsten oxide: Coupled exfoliation and fracture in a nonpolar organic medium

M. Honda, Y. Oaki, H. Imai

Chemical Communications 51 ( 49 ) 10046 - 10049 2015

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1359-7345

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An Advanced Biomimetic Approach for Crystal Growth in Nonaqueous Media: Morphology and Orientation Control of Pentacosadiynoic Acid and the Applications

M. Okaniwa, Y. Oaki, S. Kaneko, K. Ishida, H. Maki, Hideyuki, H. Imai

Chemistry of Materials 27   2627 - 2632 2015

Research paper (scientific journal), Joint Work, Accepted