Faculty Profiles - TAKEOKA, Yukikazu

Papers - TAKEOKA, Yukikazu

Division display 161 - 180 of about 251 ／ All the affair displays >>

Structural Colored Gel

Takeoka Yukikazu

JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY Vol. 22 ( 2 ) page： 123-132 2009

Structural Colored Gel Reviewed

Yukikazu Takeoka

JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY Vol. 22 ( 2 ) page： 123 - 132 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：TECHNICAL ASSOC PHOTOPOLYMERS,JAPAN

A periodically ordered interconnecting porous structure can be embodied in a chemical gel by using a closest-packed colloidal crystal as a template. The interconnecting porosity not only provides a quick response but also endows the porous gel with structural color arising from coherent Bragg optical diffraction. The structural color revealed by porous gels can be regulated by several techniques, and thus it is feasible to obtain desirable, smart, soft materials. The swelling parameter of the polymer chains in the polymer network in response to the environment may be recognized through the variation in the color of the structural colored gel by using the fine colloidal crystal. The role of the volume interactions between the polymer chains in the gel can be estimated by simply measuring the length of the gel, based on the assumption that the subchains in the polymer network under the preparation conditions behave as unperturbed Gaussian coils. This means that it is possible to determine the change at the molecular level in the gel such as the swelling parameter of the polymer chains in the polymer network in response to the environment with the naked eye only when the gel is fabricated from specific a pre-gel solution and a colloidal crystal. The linear expansion factor of the subchains was assessed by comparing the positions of the diffraction peak (lambda(max)) in a given situation and the Gaussian state at temperatures lower than the LCST of the porous gel. The periodically ordered structure with a size corresponding to the wavelength of optical light allows us to detect the behavior of polymer chains through the structural color. This review focuses on the synthesis of the structural colored porous gel and on the visualizing conformations of subchains by creating optical wavelength-sized periodically ordered structure in hydrogel. The main portion of this article was previously published in Langmuir.(19)

DOI： 10.2494/photopolymer.22.123

Web of Science

Scopus

CiNii Research

Structural Colored Gels for Tunable Soft Photonic Crystals Reviewed

Mohammad Harun-Ur-Rashid, Takahiro Seki, Yukikazu Takeoka

CHEMICAL RECORD Vol. 9 ( 2 ) page： 87 - 105 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

A periodically ordered interconnecting porous structure can be embodied in chemical gels by using closest-packed colloidal crystals as templates. The interconnecting porosity not only provides a quick response but also endows the porous gels with structural color arising from coherent Bragg optical diffraction. The structural colors revealed by porous gels can be regulated by several techniques, and thus, it is feasible to obtain desirable, smart, soft materials. A well-known thermosensitive monomer, N-isopropylacrylamide (NIPA), and other minor monomers were used to fabricate various structural colored gels. The selection of minor monomers depended on the targeted properties. This review focuses on the synthesis of templates, structural colored porous gels, and the applications of structural colored gel as smart soft materials for tunable photonic crystals. (D 2009 The Japan Chemical journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 87-105; 2009: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20169

DOI： 10.1002/tcr.20169

Web of Science

Scopus

PubMed

Template Synthesis for Stimuli-Responsive Angle Independent Structural Colored Smart Materials

Harun-Ur-Rashid Mohammad, Imran Abu Bin, Seki Takahiro, Takeoka Yukikazu, Ishii Masahiko, Nakamura Hiroshi

Transactions of the Materials Research Society of Japan Vol. 34 ( 2 ) page： 333-337 - 337 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：The Materials Research Society of Japan

Like other conventional smart materials, structural color showing smart materials inherit physical and chemical characteristics imposed by the templates. Smart Material such as structural colored gel made of photonic crystal (PC) as template, exhibits angle dependent structural color because the color arises from the Bragg optical diffraction of light from crystal planes. But angle independent or low angle dependent structural color is required for devising of display with a wide viewing angle. To meet this purpose we prepared photonic glass (PG) from silica colloidal spheres. This PG is able to exhibit structural color, which is stable against the change of the angle of view and the angle of illumination. The transmittance spectrum evidences the angle independence of the structural color of PG. The Fast Fourier Transformation and the autocorrelation function prove that we prepared an amorphous material. The existence of short range order helps PG to exhibit angle independent structural color.

DOI： 10.14723/tmrsj.34.333

CiNii Research

Template Synthesis for Stimuli-Responsive Angle Independent Structural ColoredSmart Materials Reviewed

Harun-Ur-Rashid, M, Imran, A. B, Seki, T, Ishii, M, Nakamura, H, Takeoka, Y

Transactions of the Materials Research Society Japan Vol. in press 2009

Chromic slide-ring gel based on reflection from photonic bandgap Reviewed

Harumi Murayama, Abu Bin Imran, Shusaku Nagano, Takahiro Seki, Masatoshi Kidowaki, Kohzo Ito, Yukikazu Takeoka

MACROMOLECULES Vol. 41 ( 5 ) page： 1808 - 1814 2008.3

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Here we report on a chromic slide-ring gel consisting of polyrotaxane by using a close-packed colloidal crystal as a template. In the slide-ring gel, the polymer chains with bulky end groups are not covalently cross-linked like chemical gels nor do they interact attractively like physical gets, but are topologically interlocked by figure-of-eight cross-links. The slide-ring gel has freely movable cross-links, which have a pulley effect on tensile deformation. This effect improves the mechanical properties of polymer gels. In this work, this physically and mechanically optimized polymer gel was used to make stimuli-responsive photonic band gap materials. Our gel exhibits solvatochromic behavior based on the change in structural color.

DOI： 10.1021/ma0715627

Web of Science

Scopus

*Photoregulated Worm-like Motion of Gel Reviewed

Shinohara, S., Seki, T., Sakai, T., R. Yoshida, Takeoka, Y.

Angew. Chem. Int. Ed. Vol. 97 page： 9039-9043 2008

*Fabrication of Mechanically Improved Hydrogels Using Movable Cross-linker Based on Vinyl Modified Polyrotaxane Reviewed

Imran, A. B., Seki, T., Kataoka, T., Kidowaki, M., Ito, K., Takeoka, Y.

Chemical Communications page： 5227-5229 2008

Chemical and Optical Control of Peristaltic Actuator Based on Self-Oscillating Porous Gel Reviewed

Shinohara, S., Seki, T., Sakai, T., R. Yoshida, Takeoka, Y.

Chemical Communications Vol. 4735-4737 2008

Chromic Slide-Ring Gel based on Reflection from Photonic Bandgap Reviewed

Murayama, H., Imran, A. B., Nagano, S., Seki, T., Kidowaki, M., Ito, K., Takeoka, Y.

Macromolecules Vol. 41 page： 1808-1814 2008

Chemical and optical control of peristaltic actuator based on self-oscillating porous gel Reviewed

Shu-ichi Shinohara, Takahiro Seki, Takamasa Sakai, Ryo Yoshida, Yukikazu Takeoka

CHEMICAL COMMUNICATIONS Vol. 4735-4737 ( 39 ) page： 4735 - 4737 2008

Photoregulated Wormlike Motion of a Gel Reviewed International journal

Shu-ichi Shinohara, Takahiro Seki, Takamasa Sakai, Ryo Yoshida, Yukikazu Takeoka

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 47 ( 47 ) page： 9039 - 9043 2008

Fabrication of mechanically improved hydrogels using a movable cross-linker based on vinyl modified polyrotaxane Reviewed International journal

Abu Bin Imran, Takahiro Seki, Toshiyuki Kataoka, Masatoshi Kidowaki, Kohzo Ito, Yukikazu Takeoka

CHEMICAL COMMUNICATIONS ( 41 ) page： 5227 - 5229 2008

Photoregulated wormlike motion of a gel Reviewed

Shinohara Shu-ichi, Seki Takahiro, Sakai Takamasa, Yoshida Ryo, Takeoka Yukikazu

Angewandte Chemie Vol. 120 ( 47 ) page： 9179 2008

An electro- and thermochromic hydrogel as a full-color indicator Reviewed International journal

Kazuhide Ueno, Kazuki Matsubara, Masayoshi Watanabe, Yukikazu Takeoka

ADVANCED MATERIALS Vol. 19 ( 19 ) page： 2807 - + 2007.10

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Electric-field-triggered "two-state switching" between two arbitrary structural colors (see figure) in the entire visible region at certain temperatures is shown by a stimuli-responsive chromic hydrogel. The external rapid tuning in the structural color of this hydrogel is successfully achieved by introducing a periodically ordered interconnecting porous structure.

DOI： 10.1002/adma.200700159

Web of Science

Scopus

Photochromic gels

TAKEOKA Yukikazu

Photochemistry Vol. 38 ( 2 ) page： 126-129 - 129 2007.9

Organized monolayer of thermosensitive microgel beads prepared by double-template polymerization Reviewed

Takamasa Sakai, Yukikazu Takeoka, Takahiro Seki, Ryo Yoshida

LANGMUIR Vol. 23 ( 17 ) page： 8651 - 8654 2007.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

A 2D close-packed array of thermosensitive microgel beads was prepared by the double-template polymerization method. First, a 2D colloidal crystal of silica beads with 10 mu m diameter was obtained by the solvent evaporation method. This monolayer of colloidal crystals can serve as the first template for the preparation of macroporous polystyrene. The macroporous polystyrene trapping the crystalline order can be used as a negative template for fabricating gel beads arrays. A functional surface using thermosensitive poly(N-isopropylacrylamide) gel beads array was fabricated by the double-template polymerization method.

DOI： 10.1021/la700448t

Web of Science

Scopus

PubMed

Photoresponsive slide-ring gel Reviewed

Taiga Sakai, Harumi Murayama, Shusaku Nagano, Yukikazu Takeoka, Masatoshi Kidowaki, Kohzo Ito, Takahiro Seki

ADVANCED MATERIALS Vol. 19 ( 15 ) page： 2023 - + 2007.8

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Slide-ring topological gels with mobile cross-linking units are a new class of soft materials that exhibit distinct features differing from those of conventional chemically or physically crosslinked gels. Photoresponsive behavior arising from the dynamic nature of the cross-linkers is demonstrated for a slide-ring, gel prepared by adding azobenzene units to the mobile a-cyclodextrin units of a poly(ethylene oxide)based polyrotaxane (see figure).

DOI： 10.1002/adma.200700457

Web of Science

Scopus

Biform structural colored hydrogel for observation of subchain conformations Reviewed

Yukikazu Takeoka, Takahiro Seki

MACROMOLECULES Vol. 40 ( 15 ) page： 5513 - 5518 2007.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

We prepared a biform structural colored thermosensitive gel using both a close-packed colloidal crystal and a wing of a morpho butterfly. The porous portion of the gel obtained by the close-packed colloidal crystal as a template exhibits a change in "structural color" according to the volume when the water temperature is altered. Meanwhile, the portion where tiny scales of the wing are strewn on the surface of the gel (a morpho gel) also reveals "structural color", but irrespective of the volume change. The reflection spectrum from "the morpho gel" portion provides the standard value of the peak position, lambda(max,0), indicating that the subchains in the gel are Gaussian chains. Consequently, we can estimate the linear expansion factor alpha of the subchains by comparing the peak positions of the reflection spectra from the porous gel, lambda(max), and from the morpho gel, lambda(max,0): lambda(max)/lambda(max,0) similar to alpha. We can detect the change in the conformation of subchains in the gel in response to the external perturbations surrounding the gel with the naked eye and/or spectroscopic methods through the comparison of the both structural colors.

DOI： 10.1021/ma0701078

Web of Science

Scopus

Organized Thermosensitive Microgel Bead Monolayer Prepared by Double Template Polymerization

SAKAI Takamasa, TAKEOKA Yukikazu, SEKI Takahiro, YOSHIDA Ryo

Vol. 64 ( 1 ) page： 45-49 2007.1

　 PREV - NEXT 　

<TAKEOKA, Yukikazu>

Papers - TAKEOKA, Yukikazu