The Experts below are selected from a list of 29383926 Experts worldwide ranked by ideXlab platform
Ryong Ryoo - One of the best experts on this subject based on the ideXlab platform.
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transformation of highly ordered large pore silica mesophases fm3m im3m and P6mm in a ternary triblock copolymer butanol water system
Chemical Communications, 2004Co-Authors: Freddy Kleitz, Leonid A Solovyov, Gopinathan Anilkumar, Shin Hei Choi, Ryong RyooAbstract:Exceptional control of the phase behavior of highly ordered large pore mesostructured silica (with the choice of Fm3m, Im3m or P6mm symmetry) is achieved using a triblock copolymer (EO106PO70EO106) and butanol at low acid concentrations.
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Transformation of highly ordered large pore silica mesophases (Fm3m, Im3m and P6mm) in a ternary triblock copolymer–butanol–water system
Chemical communications (Cambridge England), 2004Co-Authors: Freddy Kleitz, Leonid A Solovyov, Gopinathan Anilkumar, Shin Hei Choi, Ryong RyooAbstract:Exceptional control of the phase behavior of highly ordered large pore mesostructured silica (with the choice of Fm3m, Im3m or P6mm symmetry) is achieved using a triblock copolymer (EO106PO70EO106) and butanol at low acid concentrations.
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synthesis of thermally stable mesoporous cerium oxide with nanocrystalline frameworks using mesoporous silica templates
Chemical Communications, 2003Co-Authors: S C Laha, Ryong RyooAbstract:Highly ordered mesoporous cerium oxides, composed of nanocrystalline pore walls and exhibiting high thermal stability even at 973 K, were synthesized using mesoporous silica templates with hexagonal P6mm and cubic Ia3d symmetries.
Ching Yen Lin - One of the best experts on this subject based on the ideXlab platform.
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synthesis of P6mm hexagonal mesoporous carbons and silicas using pluronic f127 pf resin polymer blends
Microporous and Mesoporous Materials, 2006Co-Authors: Hong Ping Lin, Chih Yuan Tang, Chun Yi Changchien, Ching Yen LinAbstract:Abstract A miscible polymer blend of Pluronic F127 and phenol–formaldehyde (PF) resin through the interaction of multiple hydrogen bonds was used as a new template to synthesize a well-ordered P6mm mesostructured PF resin–F127–silica composite. By using that dual-function composite, the mesoporous silica was obtained from calcination, and mesoporous carbon was generated after carbonization and HF-etching. Both the mesoporous silica and carbons have the same morphology of hierarchical micro-fibers and the well-ordered P6mm hexagonal mesostructures. Because of the hydrophobicity of the PF resin, blending with the PF resin can induce a mesophase transformation in the PF resin–F127–silica composite. At PF resin/F127 weight ratio of 0.75, a transformation from Im3m 3D-cubic to P6mm 2D-hexagonal mesostructure occurred. In addition to F127, other block copolymers can also blend well with PF resin and these polymer blends were utilized as well, and these polymer blends were utilized to produce the mesoporous carbons and silicas of different pore sizes. In practice, this polymer blending method can provide an efficient way to synthesize the mesoporous silicas and carbons by the non-volatile and inexpensive polymers.
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Synthesis of P6mm hexagonal mesoporous carbons and silicas using Pluronic F127–PF resin polymer blends
Microporous and Mesoporous Materials, 2006Co-Authors: Hong Ping Lin, Chun Yi Chang-chien, Chih Yuan Tang, Ching Yen LinAbstract:Abstract A miscible polymer blend of Pluronic F127 and phenol–formaldehyde (PF) resin through the interaction of multiple hydrogen bonds was used as a new template to synthesize a well-ordered P6mm mesostructured PF resin–F127–silica composite. By using that dual-function composite, the mesoporous silica was obtained from calcination, and mesoporous carbon was generated after carbonization and HF-etching. Both the mesoporous silica and carbons have the same morphology of hierarchical micro-fibers and the well-ordered P6mm hexagonal mesostructures. Because of the hydrophobicity of the PF resin, blending with the PF resin can induce a mesophase transformation in the PF resin–F127–silica composite. At PF resin/F127 weight ratio of 0.75, a transformation from Im3m 3D-cubic to P6mm 2D-hexagonal mesostructure occurred. In addition to F127, other block copolymers can also blend well with PF resin and these polymer blends were utilized as well, and these polymer blends were utilized to produce the mesoporous carbons and silicas of different pore sizes. In practice, this polymer blending method can provide an efficient way to synthesize the mesoporous silicas and carbons by the non-volatile and inexpensive polymers.
Shunai Che - One of the best experts on this subject based on the ideXlab platform.
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Enhanced release of the poorly soluble drug itraconazole loaded in ordered mesoporous silica
Science China Chemistry, 2015Co-Authors: Xiao Liu, Shunai CheAbstract:It is known that the energy of the amorphous state of itraconazole loaded in ordered mesoporous materials is high relative to that of the crystalline state and is responsible for enhanced solubility and dissolution rate. We investigated the effects of particle size (0.7–5 μm), mesostructure (2D P6mm, cubic Ia-3d and cubic Fm-3m) and pore size (2.2–15.4 nm) of mesoporous silicas on the release performance of itraconazole. Results indicated that the release performance was not influenced by the particle sizes tested here, that the release performance increased with increasing pore diameter due to the lower probability of drug molecules colliding to recrystallize in large pores, and that the release performance was decreased in the cage-type pore structure (Fm-3m) compared to that in the cylindrical pore structures (P6mm and Ia-3d) because of the small entrance to the cagelike pores that retards the drug release.
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DNA–Silica Mineralization: The Formation of Exceptional Two Dimensional-Square p4mm Symmetry by a Structural Transformation
Chemistry of Materials, 2012Co-Authors: Lu Han, Chenyu Jin, Ben Liu, Shunai CheAbstract:DNA–silica complex (DSC) mesocrystals have been synthesized by the self-assembly of DNA as template, N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMAPS) as costructure directing agent (CSDA), and tetraethyl orthosilicate (TEOS) as the silica source. A full-scale synthesis-field diagram of DSCs has been constructed, and fibrous products, two-dimensional (2D)-hexagonal P6mm, and 2D-square p4mm platelets have been obtained by varying the synthetic conditions. The rare 2D-square structure possessed an inconsistent hexagonal morphology and appeared as the dominant mesostructure. The combination of X-ray diffraction patterns, scanning electron microscopy images, and high-resolution transmission electron microscopy images provided visible evidence for the mesostructural constructions of the 2D-square symmetry that transformed from the 2D-hexagonal symmetry. The driving force for this transformation seems to be the polymerization of the silica species during synthesis, which caused a decrease in the ...
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dna silica mineralization the formation of exceptional two dimensional square p4mm symmetry by a structural transformation
Chemistry of Materials, 2012Co-Authors: Lu Han, Chenyu Jin, Ben Liu, Shunai CheAbstract:DNA–silica complex (DSC) mesocrystals have been synthesized by the self-assembly of DNA as template, N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMAPS) as costructure directing agent (CSDA), and tetraethyl orthosilicate (TEOS) as the silica source. A full-scale synthesis-field diagram of DSCs has been constructed, and fibrous products, two-dimensional (2D)-hexagonal P6mm, and 2D-square p4mm platelets have been obtained by varying the synthetic conditions. The rare 2D-square structure possessed an inconsistent hexagonal morphology and appeared as the dominant mesostructure. The combination of X-ray diffraction patterns, scanning electron microscopy images, and high-resolution transmission electron microscopy images provided visible evidence for the mesostructural constructions of the 2D-square symmetry that transformed from the 2D-hexagonal symmetry. The driving force for this transformation seems to be the polymerization of the silica species during synthesis, which caused a decrease in the ...
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Growth of Mesoporous Silica Film with Vertical Channels on Substrate Using Gemini Surfactants
Chemistry of Materials, 2011Co-Authors: Lu Han, Zhang Jiang, Zhehao Huang, Ji Feng, Yuan Yao, Shunai CheAbstract:Mesoporous silica films with 2D hexagonal P6mm structured vertical channels were simply synthesized by using both anionic and cationic gemini surfactants. The morphology of the films could be optimized by adding ethanol to control the hydrolysis of TEOS and the chain volume of the gemini surfactants.
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Molecular design of the surfactant and the co-structure-directing agent (CSDA) toward rational synthesis of targeted anionic surfactant templated mesoporous silica
Journal of Materials Chemistry, 2007Co-Authors: Chuanbo Gao, Yasuhiro Sakamoto, Osamu Terasaki, Kazutami Sakamoto, Shunai CheAbstract:The formation of anionic surfactant templated mesoporous silica (AMS) is investigated from the perspective of the geometrical molecular design of the surfactant and the co-structure-directing agent (CSDA) toward the rational synthesis of the targeted mesostructure. Increasing the geometrical size of two types of head group of the anionic surfactant in the order (i) sulfonate, sulfate and phosphate, and (ii) carboxylate, N-acylalanate/N-acylglycinate and N-acylglutamate, resulted in the mesophase changing from a disordered or lamellar phase to two-dimensional (2D) hexagonal (P6mm) and three-dimensional (3D) cage-type (hexagonal and a modulated cubic phase) with increasing order of the organic/inorganic interface curvature. A change in the chain length of the surfactant also led to different surfactant packing and mesophase interfacial curvatures, and resulted in a change in mesophase from a modulated cage-type mesophase to cubic Fdm, cubic Pmn and a disordered cage-type mesophase. The geometrical change in the CSDA resulted in an increasing micellar curvature in the order: aminopropyl < N-methylaminopropyl < N,N-dimethylaminopropyl trimethoxysilane, which led to a change of mesophase from bicontinuous cubic Pnm to 2D-hexagonal P6mm. An increase in the CSDA/surfactant ratio in the synthesis gave rise to the mesophase change from a disordered cage-type mesophase to cubic Fmm or from lamellar to 2D-hexagonal P6mm, and elemental analysis results showed that the mesoporous silicas have an increased loading of organic moieties using the CSDA method.
Galen D Stucky - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of highly ordered mesoporous silica materials using sodium silicate and amphiphilic block copolymers
Chemical Communications, 2000Co-Authors: Ji Man Kim, Galen D StuckyAbstract:A commercially important synthetic approach to highly ordered mesoporous silica materials (SBA-family) with 2-D hexagonal (P6mm), 3-D hexagonal (P63/mmc) and cubic (Im3m and Pm3m) structures, using sodium silicate as the silica source and amphiphilic block copolymers as the structure-directing agents is demonstrated.
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NONIONIC TRIBLOCK AND STAR DIBLOCK COPOLYMER AND OLIGOMERIC SURFACTANT SYNTHESES OF HIGHLY ORDERED, HYDROTHERMALLY STABLE, MESOPOROUS SILICA STRUCTURES
Journal of the American Chemical Society, 1998Co-Authors: Dongyuan Zhao, Jianglin Feng, Bradley F Chmelka, Galen D StuckyAbstract:A family of highly ordered mesoporous (20−300 A) silica structures have been synthesized by the use of commercially available nonionic alkyl poly(ethylene oxide) (PEO) oligomeric surfactants and poly(alkylene oxide) block copolymers in acid media. Periodic arrangements of mescoscopically ordered pores with cubic Im3m, cubic Pm3m (or others), 3-d hexagonal (P63/mmc), 2-d hexagonal (P6mm), and lamellar (Lα) symmetries have been prepared. Under acidic conditions at room temperature, the nonionic oligomeric surfactants frequently form cubic or 3-d hexagonal mesoporous silica structures, while the nonionic triblock copolymers tend to form hexagonal (P6mm) mesoporous silica structures. A cubic mesoporous silica structure (SBA-11) with Pm3m diffraction symmetry has been synthesized in the presence of C16H33(OCH2CH2)10OH (C16EO10) surfactant species, while a 3-d hexagonal (P63/mmc) mesoporous silica structure (SBA-12) results when C18EO10 is used. Surfactants with short EO segments tend to form lamellar mesost...
Hong Ping Lin - One of the best experts on this subject based on the ideXlab platform.
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synthesis of P6mm hexagonal mesoporous carbons and silicas using pluronic f127 pf resin polymer blends
Microporous and Mesoporous Materials, 2006Co-Authors: Hong Ping Lin, Chih Yuan Tang, Chun Yi Changchien, Ching Yen LinAbstract:Abstract A miscible polymer blend of Pluronic F127 and phenol–formaldehyde (PF) resin through the interaction of multiple hydrogen bonds was used as a new template to synthesize a well-ordered P6mm mesostructured PF resin–F127–silica composite. By using that dual-function composite, the mesoporous silica was obtained from calcination, and mesoporous carbon was generated after carbonization and HF-etching. Both the mesoporous silica and carbons have the same morphology of hierarchical micro-fibers and the well-ordered P6mm hexagonal mesostructures. Because of the hydrophobicity of the PF resin, blending with the PF resin can induce a mesophase transformation in the PF resin–F127–silica composite. At PF resin/F127 weight ratio of 0.75, a transformation from Im3m 3D-cubic to P6mm 2D-hexagonal mesostructure occurred. In addition to F127, other block copolymers can also blend well with PF resin and these polymer blends were utilized as well, and these polymer blends were utilized to produce the mesoporous carbons and silicas of different pore sizes. In practice, this polymer blending method can provide an efficient way to synthesize the mesoporous silicas and carbons by the non-volatile and inexpensive polymers.
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Synthesis of P6mm hexagonal mesoporous carbons and silicas using Pluronic F127–PF resin polymer blends
Microporous and Mesoporous Materials, 2006Co-Authors: Hong Ping Lin, Chun Yi Chang-chien, Chih Yuan Tang, Ching Yen LinAbstract:Abstract A miscible polymer blend of Pluronic F127 and phenol–formaldehyde (PF) resin through the interaction of multiple hydrogen bonds was used as a new template to synthesize a well-ordered P6mm mesostructured PF resin–F127–silica composite. By using that dual-function composite, the mesoporous silica was obtained from calcination, and mesoporous carbon was generated after carbonization and HF-etching. Both the mesoporous silica and carbons have the same morphology of hierarchical micro-fibers and the well-ordered P6mm hexagonal mesostructures. Because of the hydrophobicity of the PF resin, blending with the PF resin can induce a mesophase transformation in the PF resin–F127–silica composite. At PF resin/F127 weight ratio of 0.75, a transformation from Im3m 3D-cubic to P6mm 2D-hexagonal mesostructure occurred. In addition to F127, other block copolymers can also blend well with PF resin and these polymer blends were utilized as well, and these polymer blends were utilized to produce the mesoporous carbons and silicas of different pore sizes. In practice, this polymer blending method can provide an efficient way to synthesize the mesoporous silicas and carbons by the non-volatile and inexpensive polymers.
