The morphologies and pore architectures of mesoporous ethenylene-silica were controlled using cetyltrimethylammonium bromide （CTAB） as template and （S）-β-citronellol as a co-structure-directing agent under basic ...The morphologies and pore architectures of mesoporous ethenylene-silica were controlled using cetyltrimethylammonium bromide （CTAB） as template and （S）-β-citronellol as a co-structure-directing agent under basic conditions. When the （S）-fl-citronellol/CTAB molar ratios are in the range of 0.75--2.0, helical nanofibers were obtained. With increasing the （S）-β-citronellol/CTAB molar ratio, the lengths of the nanofibers increases. Lamellar mesopores were identified on the surfaces of the nanofibers prepared in the （S）-β-citronellol/CTAB molar ratio range of 1.5--2.0. At the （S）-fl-citronellol/CTAB molar ratio of 2.5 ： 1, nanoparticles with nanoflakes on the surfaces were obtained, The field emission scanning electron microscopy images taken after different reaction times indicated that the helical pitches of the nanofibers decreased with increasing the reaction time. Helical 1,4-phenylene-silica and methylene-silica nanofibers were also prepared. The results indicated that the morphologies and pore architectures of the obtained organic-inorganic hybrid silicas are also sensitive to the hybrid silica precursors. Helical ethenylene-silica nanofibers with lamellar mesopores on their surfaces can be also prepared using the mixtures of CTAB and racemic eitronellol within a narrower citronellol/CTAB molar ratio range.展开更多
Mesoporous 1,4-phenylene-silica nanorings were prepared using cetyltrimethylammonium bromide （CTAB） and （S）-2-methyl-l-butanol as a chiral dopant in concentrated aqueous NH3 solutions. Transmission electron mi- cr...Mesoporous 1,4-phenylene-silica nanorings were prepared using cetyltrimethylammonium bromide （CTAB） and （S）-2-methyl-l-butanol as a chiral dopant in concentrated aqueous NH3 solutions. Transmission electron mi- croscopy images of the samples indicated that the nanorings were formed by bending nanorods 360°. With increasing the stirring speed or the （S）-2-methyl-l-butanol/CTAB molar ratio, the morphologies of mesoporous 1,4-phenylene-silicas changed from helical nanofibers to nanorings, and then to nano-saddles. Circular dichroism spectra of these hybrid silicas indicated that they were chiral.展开更多
The morphology, pore architecture and crystallinity of the mesoporous 1,4-phenylene-silicas were controlled using the mixtures of cetyltrimethylammonium bromide （CTAB） and sodium dodecylsulfate （SDS）. When the SDS...The morphology, pore architecture and crystallinity of the mesoporous 1,4-phenylene-silicas were controlled using the mixtures of cetyltrimethylammonium bromide （CTAB） and sodium dodecylsulfate （SDS）. When the SDS/CTAB molar ratio increased from 0 to 1.0, the morphology of the mesoporous 1,4-phenylene-silicas changed in a sequence of sphere, hexagonal short rod, worm-like, bent flake and flower-like structure; the pore architecture of them changed from a hexagonal arranged tubular structure to a lamellar one; and the organization of the smallest repeat units within the wall changed from a random structure to a crystalline structure. At the SDS/CTAB molar ratios of 0.3 and 0.5, 1,4-phenylene-silica nanofibers with lamellar mesopores outside and tubular pore channels inside were obtained. The lamellar mesopores should be formed by merging the rod-like micelles during the reaction process.展开更多
基金Project supported by Program of Innovative Research Team of Soochow University, the Jiangsu Planned Projects for Postdoctoral Research Funds, Program for New Century Excellent Talents in University （NCET-08-0698） and National Natural Science Foundation of China （No. 20871087）.
文摘The morphologies and pore architectures of mesoporous ethenylene-silica were controlled using cetyltrimethylammonium bromide （CTAB） as template and （S）-β-citronellol as a co-structure-directing agent under basic conditions. When the （S）-fl-citronellol/CTAB molar ratios are in the range of 0.75--2.0, helical nanofibers were obtained. With increasing the （S）-β-citronellol/CTAB molar ratio, the lengths of the nanofibers increases. Lamellar mesopores were identified on the surfaces of the nanofibers prepared in the （S）-β-citronellol/CTAB molar ratio range of 1.5--2.0. At the （S）-fl-citronellol/CTAB molar ratio of 2.5 ： 1, nanoparticles with nanoflakes on the surfaces were obtained, The field emission scanning electron microscopy images taken after different reaction times indicated that the helical pitches of the nanofibers decreased with increasing the reaction time. Helical 1,4-phenylene-silica and methylene-silica nanofibers were also prepared. The results indicated that the morphologies and pore architectures of the obtained organic-inorganic hybrid silicas are also sensitive to the hybrid silica precursors. Helical ethenylene-silica nanofibers with lamellar mesopores on their surfaces can be also prepared using the mixtures of CTAB and racemic eitronellol within a narrower citronellol/CTAB molar ratio range.
基金This work was partially supported by Program ofInnovative Research Team of Soochow University, the Jiangsu Planned Projects for Postdoctoral Research Funds, Program for New Century Excellent Talents in University （No. NCET-08-0698）, and National Natural Science Foundation of China （No. 20871087）.
文摘Mesoporous 1,4-phenylene-silica nanorings were prepared using cetyltrimethylammonium bromide （CTAB） and （S）-2-methyl-l-butanol as a chiral dopant in concentrated aqueous NH3 solutions. Transmission electron mi- croscopy images of the samples indicated that the nanorings were formed by bending nanorods 360°. With increasing the stirring speed or the （S）-2-methyl-l-butanol/CTAB molar ratio, the morphologies of mesoporous 1,4-phenylene-silicas changed from helical nanofibers to nanorings, and then to nano-saddles. Circular dichroism spectra of these hybrid silicas indicated that they were chiral.
基金Project supported by the Program of Innovative Research Team of Soochow University, Program for New Century Excellent Talents in University （No. NCET-08-0698） and the National Natural Science Foundation of China （No. 20871087）.
文摘The morphology, pore architecture and crystallinity of the mesoporous 1,4-phenylene-silicas were controlled using the mixtures of cetyltrimethylammonium bromide （CTAB） and sodium dodecylsulfate （SDS）. When the SDS/CTAB molar ratio increased from 0 to 1.0, the morphology of the mesoporous 1,4-phenylene-silicas changed in a sequence of sphere, hexagonal short rod, worm-like, bent flake and flower-like structure; the pore architecture of them changed from a hexagonal arranged tubular structure to a lamellar one; and the organization of the smallest repeat units within the wall changed from a random structure to a crystalline structure. At the SDS/CTAB molar ratios of 0.3 and 0.5, 1,4-phenylene-silica nanofibers with lamellar mesopores outside and tubular pore channels inside were obtained. The lamellar mesopores should be formed by merging the rod-like micelles during the reaction process.
