Faculty Profiles - TAKEOKA, Yukikazu

Papers - TAKEOKA, Yukikazu

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Recent advances in hydrogels in terms of fast stimuli responsiveness and superior mechanical performance Reviewed

竹岡敬和

Polymer Journal Vol. 42 page： 839 - 851 2010

ゲルの体積相転移

竹岡敬和

高分子 56 page： 26 - 27 2007

デルの体積相転移

竹岡敬和

高分子 56 page： 26 - 27 2007

Voluthe Phase Transition of Gel (1978: Toyoichi Tanaka)

NAGAYAMA Kuniaki, TAKEOKA Yukikazu

Kobunshi Vol. 56 ( 1 ) page： 26 - 27 2007

Design of novel microactuator made of self-oscillating gel by assembling the microbeads and controlling their crosslinking structures

Sakai T., Kinoshita M., Takeoka Y., Seki T., Yoshida R.

Polymer Preprints, Japan Vol. 55 ( 2 ) page： 4538 - 4539 2006.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

We have prepared the self-oscillating polymer and gels composed of poly(N-isopropylacrylamide) in which ruthenium tris(2,2'-bipyridine) (Ru(bpy)3), a catalyst for the Belousov-Zhabotinsky (BZ) reaction, is covalently bonded to the polymer chain. They change the conformation rhythmically and periodically without external stimuli in closed system. In order to investigate crosslinking effect of the polymers, phase transition behaviors of the linear polymer and the nano-gel beads were analyzed by measuring the transmittance and fluorescence intensity. Furthermore, by arraying the gel beads on the substrate surface, we designed the nano-conveyer which enables to transport substances added on the surface with the propagation of chemical waves induced by the BZ reaction. Artificial worm-like gel having gradient structure was also obtained by unidirectional photopolymerization.

Scopus

Selective surface modification of PNIPA gel surface by imprinting method

Ueda A., Takeoka Y., Seki T.

Polymer Preprints, Japan Vol. 55 ( 2 ) page： 4573 - 4574 2006.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

In recent years, the study of the surface properties of gels have become the focus of much interest due to their function similarity to living body and biocompatibility. We think that the establishment of the innovative approach to the method bring a creation of custom-made surface-functionalized gels. In this study, we obtained surface-functionalized gels by an approach to introduce sulfonic acid group to the surface of a gel by molecularly imprinting method (Scheme 1). To elucidate the presence of the sulfonic acid group on the surface of the gel, we attempted the adsorption test of amino-group modified fluorescence microbeads onto the surface of the gel. The microbeads equably adsorbed on the surface of the gel prepared by this method.

Scopus

Preparation and optical properties of ordered arrays of glucose-responsible submicrogel particles trapped in inverse opal polystyrene

Honda M., Takeoka Y., Seki T., Kataoka K.

Polymer Preprints, Japan Vol. 55 ( 2 ) page： 4583 - 4584 2006.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

First, we obtained a closest-packing photonic crystal that acts as a photonic crystal composed of monodisperse silica particles 300 nm in diameter. A styrene monomer containing an initiator was infiltrated into the crystal and was polymerized so as to trap the crystalline structure. The composite film was soaked in HF solution to remove the silica particles completely. Then the resulting inverse opal polystyrene film with interconnecting porous structure could serve as a template to obtain glucose-responsible nanogel particles. We found that the intensity of Bragg diffraction is altered by the existence of glucose due to the swelling of the embedded nanogel particles. Such behavior was dependent on the glucose concentration.

Scopus

Photomechanical effect of azobenzene liquid crystalline gel impregnated with low molecular weight liquid crystals

Hayata Y., Nagano S., Takeoka Y., Seki T.

Polymer Preprints, Japan Vol. 55 ( 2 ) 2006.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

Azobenzene liquid crystalline gels were prepared by photopolymerization in the Isotropic state. The LC gels with porous structure were prepared by the method to infiltrate a monomer mixture into the closest-packing silica colloid crystals at 100°C. The composite film was soaked in HF solution to remove the silica particles completely. Both porous liquid crystalline gels and non-porous gels were impregnated with 5 CB. We confirmed the photo-induced volume change for both LC gel systems. The effect of introduction of porous structure will be discussed.

Scopus

Design of functional surface by arraying self-oscillationg nano-gel beads

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

Polymer Preprints, Japan Vol. 55 ( 1 ) 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

We have prepared the self-oscillating polymer and gels composed of poly(N-isopropylacrylamide) in which ruthenium tris(2,2′-bipyridine) (Ru(bpy)s), a catalyst for the BelousovZhabotinsky (BZ) reaction, is covalently bonded to the polymer chain. The periodic conformational or swelling-deswelling changes of the polymer and nano-gel beads were measured as the optical transmittance changes of the solution. In order to investigate crosslinking effect of the polymers, phase transition behaviors of the linear polymer and the nano-gel beads were analyzed by measuring the transmittance and fluorescence intensity. Furthermore, by arraying the gel beads on the substrate surface, we designed the nano-conveyer which enables to transport substances added on the surface with the propagation of chemical waves induced by the BZ reaction.

Scopus

Swelling behavior of polyrotaxane gels exhibiting structural colors

Murayama H., Nagano S., Ito K., Takeoka Y., Seki T.

Polymer Preprints, Japan Vol. 55 ( 1 ) 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

A new type of gel called topological gel having mobile cross-links can be obtained by using polyrotaxanes as gel components. In the present study, polyrotaxane gels with inverse opal structures were prepared by templating a colloidal crystal of silica. The preparative conditions such as selection of crosslinking reagent, temperature, solvent are investigated in detail. As the consequence, polyrotaxane gels showing a structural color were obtained. The reflection wavelength was exactly correlated with the degree of swelling.

Scopus

Preparation of crosslinked azobenzene liquid crystalline polymer films and their direct evaluation by UV-Vis absorption spectrum

Hayata Y., Nagano S., Takeoka Y., Seki T.

Polymer Preprints, Japan Vol. 55 ( 1 ) 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

Crosslinked side-chain liquid crystalline polymers films containing azobenzene moieties were prepared by photopolymerization in the liquid crystalline state. Due to the small amount of azobenzene moieties introduced, the liquid crystalline phase transition and photoisomerization behavior of this film could be directly evaluated by UV-Vis absorption spectrum.

Scopus

Preparation and optical properties of ordered arrays of glucose-responsible nanogel particles trapped in inverse opal polystyrene

Honda M., Takeoka Y., Seki T., Kataoka K.

Polymer Preprints, Japan Vol. 55 ( 1 ) 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

First, we obtained a closest-packing photonic crystal that acts as a photonic crystal composed of monodisperse silica particles 300 nm in diameter. A styrene monomer containing an initiator was infiltrated into the crystal and was polymerized so as to trap the crystalline structure, The composite film was soaked in HF solution to remove the silica particles completely. Then the resulting inverse opal polystyrene film with interconnecting porous structure could serve as a template to obtain glucose-responsible nanogel particles. We found that the intensity of Bragg diffraction is altered by the existence of glucose due to the swelling of the embedded nanogel particles. Such behavior was dependent on the glucose concentration.

Scopus

Patterning of NIPA gel surface by surface imprinting method

Ueda A., Takeoka Y., Seki T.

Polymer Preprints, Japan Vol. 55 ( 1 ) 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

We fabricated the patterning of sulfonic acid groups on the surface of NIPA gel by surface imprinting method as following procedures: 1) amino-terminated SAMs was formed onto a silicon substrate. 2) UV light was irradiated on an amino-terminated SAMs through a photomask. 3) a vinyl monomer having sulfonic acid group was electrostatically coupled with the amino group of the SAMs. 4) A gel is prepared on the vinyl monomer modified silicon substrate by free-radical polymerization. We attempted the adsorption test of amino-group modified fluorescence microbeads onto the surface of the gel (figure 2). These results indicate that the surface modified gel membrane with sulfonic acid can be fabricated from this surface molecularly imprinting method.

Scopus

ゲル微粒子集積体の構築とその光学的挙動

竹岡敬和

ケミカルエンジニアリング (印刷中) 2006

コロイド結晶をテンプレートとした構造色ゲルの作製とセンサーデバイスへの応用

竹岡敬和

ポリマーフロンティア21 (印刷中) 2006

Design of nano-oscillation using self-oscillating polymer and the analysis of cooperative effects

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

Polymer Preprints, Japan Vol. 54 ( 2 ) page： 4755 - 4756 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

We have prepared the self-oscillating polymer and gels composed of poly(N-isopropylacrylamide) in which ruthenium tris(2,2′-bipyridine) (Ru(bpy) 3), a catalyst for the Belousov-Zhabotinsky (BZ) reaction, is covalently bonded to the polymer chain. The periodic conformational or swelling-deswelling changes of the polymer and nano-gel beads were measured as the optical transmittance changes of the solution. In order to investigate crosslinking effect of the polymers, phase transition behaviors of the linear polymer and the nano-gel beads were analyzed by measuring the transmittance and fluorescence intensity. Furthermore, by arraying the gel beads on the substrate surface, we designed the nano-conveyer which enables to transport substances added on the surface with the propagation of chemical waves induced by the BZ reaction.

Scopus

Synthesis of photo-responsive porous poly(NIPA) gel and evaluation of its optical properties

Matsubara K., Watanabe M., Takeoka Y.

Polymer Preprints, Japan Vol. 54 ( 1 ) 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

A thermosensitive inverse-opal-type porous gel having pendant azobenzene groups, prepared by using a closest-packing SiO2 colloidal crystal as a template, can reversibly change its structural color in response to thermo- and photo-stimuli in water. With varying temperature, the peak values, λmax, of the reflection spectra for the porous gel continuously shifted until the gel network expansion reaches a new equilibrium state, because the gel underwent an isotropic volume change. In contrast, upon UV irradiation from the normal to the gel surface, a new λmax possessing a wavelength longer than that in the dark appeared at constant temperatures, accompanied by the photoinduced volume change of the gel. The change in the λmax could be reversed to the original state by exposure to Vis light through a different process of the variation in the λmax upon the UV irradiation. We concluded that the photo-responsive porous gel undergoes a photoinduced bistable volume change by photo-stimuli. This system enables to convert a two-state isomerization model of the azobenzene molecules into the two-state volume and/or lattice constant change of the porous gel having the azobenzene groups.

Scopus

Surface modification of gel by molecularly imprinting method

Ueda A., Takeoka Y., Seki T.

Polymer Preprints, Japan Vol. 54 ( 1 ) 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

We fabricated a surface modified gel membrane by a molecularly imprinting method as following procedures: 1) a number of amino-terminated SAMs were formed onto a glass substrate by CVD method. 2) a vinyl monomer having sulfonic acid group was electrostatically coupled with the amino group of the SAMs. 3) A gel is prepared on the vinyl monomer modified glass substrate by free-radical polymerization. We are planning on observing the surface state of the gel by a contact angle measurement, XPS and a fluorescent maicrobeads adsorption method.

Scopus

Structural colored gel

Takeoka Y.

Polymer Preprints, Japan Vol. 54 ( 2 ) page： 4702 - 4704 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

"Smart" porous gels with different optical behaviors were synthesized by quantitative adjustment of the cross-linker in pre-gel solutions. A periodically ordered interconnecting porous structure could be created in the gels by using a closest-packing silica colloidal crystal as a template. The interconnecting porosity provides fast response to changes in temperature through the reversible swelling and shrinking of the gels, while the periodically ordered mesoscopic structure endows the porous gels with structural color, which can be tuned by simply changing the amount of the cross-linker in the pre-gel solutions.

Scopus

Proposal of multicolor electrochromic polymer gels

Ueno K., Matsubara K., Watanabe M., Takeoka Y.

Polymer Preprints, Japan Vol. 54 ( 2 ) page： 4709 - 4710 2005.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan

Periodically ordered macroporous gels having ionized groups, which can exhibit a monochromatic structural color and undergo a drastic change in the color in response to external stimuli, were prepared by thermally induced radical copolymerization of N-isopropylacrylamide (NIPA) and methacrylic acid (MAAc) using a close-packed silica colloidal crystal as a template. The temperature and pH sensitive optical properties were investigated by reflection spectroscopy. Furthermore, we demonstrated that such pH sensitive optical properties could be manipulated by local pH change induced by water electrolysis. In other words, the electrochromism resulting from the change in structural color was successfully achieved. It was also explored that multicolor electrochromism of the porous gel could be actualized by temperature control of the solution together with the application of sufficient voltage. Moreover, the dynamic optical properties were investigated by the analysis of the diffraction peaks and the actual observation of the volume change behavior. The optical dynamics was critically influenced by the volume change anisotropy of the porous gels.

Scopus

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Papers - TAKEOKA, Yukikazu