The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Atsushi Takahara - One of the best experts on this subject based on the ideXlab platform.
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Biobased Polymer Coating Using Catechol Derivative Urushiol
Langmuir : the ACS journal of surfaces and colloids, 2016Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Jin Nishida, Tomoyuki Ohishi, Atsushi TakaharaAbstract:We have investigated the mechanism of the superior mechanical robustness of coated thin films of the Catechol Derivative urushiol. We synthesized hydrogenated urushiol (h-urushiol) by hydrogenating the double bonds in the long alkyl side chain of urushiol, and the physical properties of thin films of mixtures of urushiol and h-urushiol were evaluated. Atomic force microscopy observations revealed that these coated thin films have a homogeneous surface with no phase separation, regardless of the h-urushiol content, arising from the similarity of the chemical structures. The films showed good adhesive properties because the adhesion originates from the Catechol structure. In contrast, curing time depended strongly upon the h-urushiol content. The curing of the h-urushiol thin film took 12 h, whereas the urushiol thin film was cured within 10 min. Moreover, the strain-induced elastic buckling instability for mechanical measurements test and the bulge test confirmed that the increase in the h-urushiol content...
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Biobased Polymer Coating Using Catechol Derivative Urushiol
2016Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Jin Nishida, Tomoyuki Ohishi, Atsushi TakaharaAbstract:We have investigated the mechanism of the superior mechanical robustness of coated thin films of the Catechol Derivative urushiol. We synthesized hydrogenated urushiol (h-urushiol) by hydrogenating the double bonds in the long alkyl side chain of urushiol, and the physical properties of thin films of mixtures of urushiol and h-urushiol were evaluated. Atomic force microscopy observations revealed that these coated thin films have a homogeneous surface with no phase separation, regardless of the h-urushiol content, arising from the similarity of the chemical structures. The films showed good adhesive properties because the adhesion originates from the Catechol structure. In contrast, curing time depended strongly upon the h-urushiol content. The curing of the h-urushiol thin film took 12 h, whereas the urushiol thin film was cured within 10 min. Moreover, the strain-induced elastic buckling instability for mechanical measurements test and the bulge test confirmed that the increase in the h-urushiol content decreased the mechanical strength. Because the double bonds in the urushiol side chain contribute to forming the highly cross-linked structure, the lack of double bonds in h-urushiol resulted in the slow curing and low mechanical strength. Interestingly, the mechanical robustness started to increase over 80 mol % h-urushiol. The saturated long alkyl side chain of h-urushiol faced the surface, and the regular structure of the uniform side chain may improve the mechanical properties of the coated film. Our results will help to develop biomimetic Catechol-based coatings
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spray assisted nanocoating of the biobased material urushiol
Langmuir, 2015Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:We have demonstrated the spray-assisted coating of the Catechol Derivative, urushiol. Spraying a mixture of urushiol and iron(II) acetate formed a uniform coating about 10 nm thick, as confirmed by AFM observations. XPS measurements revealed that various substrates, including polyolefins and thermosetting resins, were successfully coated with urushiol. The coating showed good solvent tolerance and coating adhesion after baking at 100 °C for 10 min or after aerobic oxidation for several days. Interestingly, quartz crystal microbalance (QCM) measurements and strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) revealed that density and Young’s modulus of the spray-assisted nanocoatings were higher than those of spray-coated samples. Moreover, the coating was uninvolved in physical properties except surface properties, as demonstrated by several experiments. Because urushiol is a promising biobased material, our unique spray-assisted coating technique could provide a general appr...
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Surface texturing of natural ‘urushi’ thermosetting polymer thin films
Polymer Journal, 2014Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:Japanese lacquer, known as urushi , is a traditional natural resin used for numerous applications, including tableware, art and furniture. The main component of urushi is urushiol, which is a Catechol Derivative with a long unsaturated hydrocarbon side chain. Utilizing the characteristics of urushiol as a thermoset, we have demonstrated the surface texturing of an urushi thin film with a thermal imprinting technique. Thermal imprinting was conducted at 100 °C for 10 min by pressing a patterned mold onto the film, and an indented surface that replicated the surface of the mold was obtained. The static water contact angle was changed from 70±0.5° to 112±3° after the fabrication of pillared patterns on the surface. Moreover, the imprinted line and space patterns caused strong anisotropic wetting depending on the direction. Our results demonstrate that the texturing of urushi thin films is a useful technique for controlling the wettability of natural thermoset urushi thin films. Surface texturing of Catechol Derivative urushiol was achieved using a thermal imprinting technique. An indented surface was obtained by thermal curing at 100 °C for 10 min while pressing an urushi film with a patterned mold. The indented surface enhanced the static water contact angle in comparison with the flat urushi film.
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Characterization of Catechol‐containing natural thermosetting polymer “urushiol” thin film
Journal of Polymer Science Part A: Polymer Chemistry, 2013Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:Urushi (oriental lacquer) is made from the sap of Rhus vernicifera and consists mainly of the Catechol Derivative urushiol. Thermal curing of urushiol, unlike other Catechol Derivatives, is possible because of the unsaturated double bonds in the long hydrocarbon side chain. We described here a simple, efficient method to produce a thermally cross-linked urushi thin film using iron(II) acetate as the additive. The cured thin films showed robust, flexible feature as confirmed by strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) and bulging experiments. In contrast, a thin film of poly(dopamine) that is a typical Catechol Derivative without long hydrocarbon side chain showed brittleness. The long hydrocarbon side chain of urushiol plays an important role for both thermal processability and superior mechanical properties of the material. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3688–3692
Hirohmi Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Biobased Polymer Coating Using Catechol Derivative Urushiol
Langmuir : the ACS journal of surfaces and colloids, 2016Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Jin Nishida, Tomoyuki Ohishi, Atsushi TakaharaAbstract:We have investigated the mechanism of the superior mechanical robustness of coated thin films of the Catechol Derivative urushiol. We synthesized hydrogenated urushiol (h-urushiol) by hydrogenating the double bonds in the long alkyl side chain of urushiol, and the physical properties of thin films of mixtures of urushiol and h-urushiol were evaluated. Atomic force microscopy observations revealed that these coated thin films have a homogeneous surface with no phase separation, regardless of the h-urushiol content, arising from the similarity of the chemical structures. The films showed good adhesive properties because the adhesion originates from the Catechol structure. In contrast, curing time depended strongly upon the h-urushiol content. The curing of the h-urushiol thin film took 12 h, whereas the urushiol thin film was cured within 10 min. Moreover, the strain-induced elastic buckling instability for mechanical measurements test and the bulge test confirmed that the increase in the h-urushiol content...
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Biobased Polymer Coating Using Catechol Derivative Urushiol
2016Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Jin Nishida, Tomoyuki Ohishi, Atsushi TakaharaAbstract:We have investigated the mechanism of the superior mechanical robustness of coated thin films of the Catechol Derivative urushiol. We synthesized hydrogenated urushiol (h-urushiol) by hydrogenating the double bonds in the long alkyl side chain of urushiol, and the physical properties of thin films of mixtures of urushiol and h-urushiol were evaluated. Atomic force microscopy observations revealed that these coated thin films have a homogeneous surface with no phase separation, regardless of the h-urushiol content, arising from the similarity of the chemical structures. The films showed good adhesive properties because the adhesion originates from the Catechol structure. In contrast, curing time depended strongly upon the h-urushiol content. The curing of the h-urushiol thin film took 12 h, whereas the urushiol thin film was cured within 10 min. Moreover, the strain-induced elastic buckling instability for mechanical measurements test and the bulge test confirmed that the increase in the h-urushiol content decreased the mechanical strength. Because the double bonds in the urushiol side chain contribute to forming the highly cross-linked structure, the lack of double bonds in h-urushiol resulted in the slow curing and low mechanical strength. Interestingly, the mechanical robustness started to increase over 80 mol % h-urushiol. The saturated long alkyl side chain of h-urushiol faced the surface, and the regular structure of the uniform side chain may improve the mechanical properties of the coated film. Our results will help to develop biomimetic Catechol-based coatings
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spray assisted nanocoating of the biobased material urushiol
Langmuir, 2015Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:We have demonstrated the spray-assisted coating of the Catechol Derivative, urushiol. Spraying a mixture of urushiol and iron(II) acetate formed a uniform coating about 10 nm thick, as confirmed by AFM observations. XPS measurements revealed that various substrates, including polyolefins and thermosetting resins, were successfully coated with urushiol. The coating showed good solvent tolerance and coating adhesion after baking at 100 °C for 10 min or after aerobic oxidation for several days. Interestingly, quartz crystal microbalance (QCM) measurements and strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) revealed that density and Young’s modulus of the spray-assisted nanocoatings were higher than those of spray-coated samples. Moreover, the coating was uninvolved in physical properties except surface properties, as demonstrated by several experiments. Because urushiol is a promising biobased material, our unique spray-assisted coating technique could provide a general appr...
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Surface texturing of natural ‘urushi’ thermosetting polymer thin films
Polymer Journal, 2014Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:Japanese lacquer, known as urushi , is a traditional natural resin used for numerous applications, including tableware, art and furniture. The main component of urushi is urushiol, which is a Catechol Derivative with a long unsaturated hydrocarbon side chain. Utilizing the characteristics of urushiol as a thermoset, we have demonstrated the surface texturing of an urushi thin film with a thermal imprinting technique. Thermal imprinting was conducted at 100 °C for 10 min by pressing a patterned mold onto the film, and an indented surface that replicated the surface of the mold was obtained. The static water contact angle was changed from 70±0.5° to 112±3° after the fabrication of pillared patterns on the surface. Moreover, the imprinted line and space patterns caused strong anisotropic wetting depending on the direction. Our results demonstrate that the texturing of urushi thin films is a useful technique for controlling the wettability of natural thermoset urushi thin films. Surface texturing of Catechol Derivative urushiol was achieved using a thermal imprinting technique. An indented surface was obtained by thermal curing at 100 °C for 10 min while pressing an urushi film with a patterned mold. The indented surface enhanced the static water contact angle in comparison with the flat urushi film.
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Characterization of Catechol‐containing natural thermosetting polymer “urushiol” thin film
Journal of Polymer Science Part A: Polymer Chemistry, 2013Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:Urushi (oriental lacquer) is made from the sap of Rhus vernicifera and consists mainly of the Catechol Derivative urushiol. Thermal curing of urushiol, unlike other Catechol Derivatives, is possible because of the unsaturated double bonds in the long hydrocarbon side chain. We described here a simple, efficient method to produce a thermally cross-linked urushi thin film using iron(II) acetate as the additive. The cured thin films showed robust, flexible feature as confirmed by strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) and bulging experiments. In contrast, a thin film of poly(dopamine) that is a typical Catechol Derivative without long hydrocarbon side chain showed brittleness. The long hydrocarbon side chain of urushiol plays an important role for both thermal processability and superior mechanical properties of the material. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3688–3692
Aya Fujimoto - One of the best experts on this subject based on the ideXlab platform.
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Biobased Polymer Coating Using Catechol Derivative Urushiol
Langmuir : the ACS journal of surfaces and colloids, 2016Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Jin Nishida, Tomoyuki Ohishi, Atsushi TakaharaAbstract:We have investigated the mechanism of the superior mechanical robustness of coated thin films of the Catechol Derivative urushiol. We synthesized hydrogenated urushiol (h-urushiol) by hydrogenating the double bonds in the long alkyl side chain of urushiol, and the physical properties of thin films of mixtures of urushiol and h-urushiol were evaluated. Atomic force microscopy observations revealed that these coated thin films have a homogeneous surface with no phase separation, regardless of the h-urushiol content, arising from the similarity of the chemical structures. The films showed good adhesive properties because the adhesion originates from the Catechol structure. In contrast, curing time depended strongly upon the h-urushiol content. The curing of the h-urushiol thin film took 12 h, whereas the urushiol thin film was cured within 10 min. Moreover, the strain-induced elastic buckling instability for mechanical measurements test and the bulge test confirmed that the increase in the h-urushiol content...
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Biobased Polymer Coating Using Catechol Derivative Urushiol
2016Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Jin Nishida, Tomoyuki Ohishi, Atsushi TakaharaAbstract:We have investigated the mechanism of the superior mechanical robustness of coated thin films of the Catechol Derivative urushiol. We synthesized hydrogenated urushiol (h-urushiol) by hydrogenating the double bonds in the long alkyl side chain of urushiol, and the physical properties of thin films of mixtures of urushiol and h-urushiol were evaluated. Atomic force microscopy observations revealed that these coated thin films have a homogeneous surface with no phase separation, regardless of the h-urushiol content, arising from the similarity of the chemical structures. The films showed good adhesive properties because the adhesion originates from the Catechol structure. In contrast, curing time depended strongly upon the h-urushiol content. The curing of the h-urushiol thin film took 12 h, whereas the urushiol thin film was cured within 10 min. Moreover, the strain-induced elastic buckling instability for mechanical measurements test and the bulge test confirmed that the increase in the h-urushiol content decreased the mechanical strength. Because the double bonds in the urushiol side chain contribute to forming the highly cross-linked structure, the lack of double bonds in h-urushiol resulted in the slow curing and low mechanical strength. Interestingly, the mechanical robustness started to increase over 80 mol % h-urushiol. The saturated long alkyl side chain of h-urushiol faced the surface, and the regular structure of the uniform side chain may improve the mechanical properties of the coated film. Our results will help to develop biomimetic Catechol-based coatings
-
spray assisted nanocoating of the biobased material urushiol
Langmuir, 2015Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:We have demonstrated the spray-assisted coating of the Catechol Derivative, urushiol. Spraying a mixture of urushiol and iron(II) acetate formed a uniform coating about 10 nm thick, as confirmed by AFM observations. XPS measurements revealed that various substrates, including polyolefins and thermosetting resins, were successfully coated with urushiol. The coating showed good solvent tolerance and coating adhesion after baking at 100 °C for 10 min or after aerobic oxidation for several days. Interestingly, quartz crystal microbalance (QCM) measurements and strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) revealed that density and Young’s modulus of the spray-assisted nanocoatings were higher than those of spray-coated samples. Moreover, the coating was uninvolved in physical properties except surface properties, as demonstrated by several experiments. Because urushiol is a promising biobased material, our unique spray-assisted coating technique could provide a general appr...
-
Surface texturing of natural ‘urushi’ thermosetting polymer thin films
Polymer Journal, 2014Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:Japanese lacquer, known as urushi , is a traditional natural resin used for numerous applications, including tableware, art and furniture. The main component of urushi is urushiol, which is a Catechol Derivative with a long unsaturated hydrocarbon side chain. Utilizing the characteristics of urushiol as a thermoset, we have demonstrated the surface texturing of an urushi thin film with a thermal imprinting technique. Thermal imprinting was conducted at 100 °C for 10 min by pressing a patterned mold onto the film, and an indented surface that replicated the surface of the mold was obtained. The static water contact angle was changed from 70±0.5° to 112±3° after the fabrication of pillared patterns on the surface. Moreover, the imprinted line and space patterns caused strong anisotropic wetting depending on the direction. Our results demonstrate that the texturing of urushi thin films is a useful technique for controlling the wettability of natural thermoset urushi thin films. Surface texturing of Catechol Derivative urushiol was achieved using a thermal imprinting technique. An indented surface was obtained by thermal curing at 100 °C for 10 min while pressing an urushi film with a patterned mold. The indented surface enhanced the static water contact angle in comparison with the flat urushi film.
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Characterization of Catechol‐containing natural thermosetting polymer “urushiol” thin film
Journal of Polymer Science Part A: Polymer Chemistry, 2013Co-Authors: Hirohmi Watanabe, Aya Fujimoto, Atsushi TakaharaAbstract:Urushi (oriental lacquer) is made from the sap of Rhus vernicifera and consists mainly of the Catechol Derivative urushiol. Thermal curing of urushiol, unlike other Catechol Derivatives, is possible because of the unsaturated double bonds in the long hydrocarbon side chain. We described here a simple, efficient method to produce a thermally cross-linked urushi thin film using iron(II) acetate as the additive. The cured thin films showed robust, flexible feature as confirmed by strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) and bulging experiments. In contrast, a thin film of poly(dopamine) that is a typical Catechol Derivative without long hydrocarbon side chain showed brittleness. The long hydrocarbon side chain of urushiol plays an important role for both thermal processability and superior mechanical properties of the material. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3688–3692
Gilles Lemercier - One of the best experts on this subject based on the ideXlab platform.
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optical properties of a donor acceptor substituted hemi cruciform Catechol Derivative
Journal of Photochemistry and Photobiology A-chemistry, 2010Co-Authors: Christophe Aronica, Juliette Guérin, Jérôme Chauvin, Vincent Robert, Gilles LemercierAbstract:Abstract The optical properties of a novel Catechol Derivative have been studied; a very large solvatochromism of the emission spectra was observed, revealing an important low-energy intra-molecular charge-transfer. From our experiment, a chemical structure–polarizability relationship is studied according to the Lippert–Mataga correlation and compared to results obtained previously for analogous compounds. This synthetic strategy complemented with characterizations and theoretical analysis allows one to design specific charge-transfer compounds to be used as nonlinear chromophores and ligands in multifunctional complexes.
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Optical properties of a donor–acceptor-substituted “hemi-cruciform” Catechol Derivative
Journal of Photochemistry and Photobiology A-chemistry, 2010Co-Authors: Christophe Aronica, Juliette Guérin, Jérôme Chauvin, Vincent Robert, Gilles LemercierAbstract:Abstract The optical properties of a novel Catechol Derivative have been studied; a very large solvatochromism of the emission spectra was observed, revealing an important low-energy intra-molecular charge-transfer. From our experiment, a chemical structure–polarizability relationship is studied according to the Lippert–Mataga correlation and compared to results obtained previously for analogous compounds. This synthetic strategy complemented with characterizations and theoretical analysis allows one to design specific charge-transfer compounds to be used as nonlinear chromophores and ligands in multifunctional complexes.
Christophe Aronica - One of the best experts on this subject based on the ideXlab platform.
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optical properties of a donor acceptor substituted hemi cruciform Catechol Derivative
Journal of Photochemistry and Photobiology A-chemistry, 2010Co-Authors: Christophe Aronica, Juliette Guérin, Jérôme Chauvin, Vincent Robert, Gilles LemercierAbstract:Abstract The optical properties of a novel Catechol Derivative have been studied; a very large solvatochromism of the emission spectra was observed, revealing an important low-energy intra-molecular charge-transfer. From our experiment, a chemical structure–polarizability relationship is studied according to the Lippert–Mataga correlation and compared to results obtained previously for analogous compounds. This synthetic strategy complemented with characterizations and theoretical analysis allows one to design specific charge-transfer compounds to be used as nonlinear chromophores and ligands in multifunctional complexes.
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Optical properties of a donor–acceptor-substituted “hemi-cruciform” Catechol Derivative
Journal of Photochemistry and Photobiology A-chemistry, 2010Co-Authors: Christophe Aronica, Juliette Guérin, Jérôme Chauvin, Vincent Robert, Gilles LemercierAbstract:Abstract The optical properties of a novel Catechol Derivative have been studied; a very large solvatochromism of the emission spectra was observed, revealing an important low-energy intra-molecular charge-transfer. From our experiment, a chemical structure–polarizability relationship is studied according to the Lippert–Mataga correlation and compared to results obtained previously for analogous compounds. This synthetic strategy complemented with characterizations and theoretical analysis allows one to design specific charge-transfer compounds to be used as nonlinear chromophores and ligands in multifunctional complexes.