Single-handed helical silica nanotubes were prepared according to the literature procedures,using the self-assemblies of a pair of chiral cationic low-molecular-weight gelators as the templates.A chirality indicator,...Single-handed helical silica nanotubes were prepared according to the literature procedures,using the self-assemblies of a pair of chiral cationic low-molecular-weight gelators as the templates.A chirality indicator,4,4'-bis(triethoxysilyl)-1,1'-biphenyl,was developed to determine the chirality of the silica nanotubes.The chirality of the surfaces and the bulky walls of the silica nanotubes were understood from the twist of the biphenylene rings.展开更多
Left and right-handed helical barium titanate nanotubes are prepared with the impregnation of Ba(OH)2 into single-handed helical titania nanotubes.Wide angle X-ray diffraction pattern and transmission electron micro...Left and right-handed helical barium titanate nanotubes are prepared with the impregnation of Ba(OH)2 into single-handed helical titania nanotubes.Wide angle X-ray diffraction pattern and transmission electron microscopy image indicate that they are constructed by nanoparticles with a partially crystalline structure.The diffuse reflertance circular dichroism spectra indicate that they exhibit optical activity which was proposed to originate from chiral defects on the inner surfaces of the nanotubes.Both the dielectric constant and tanδ decrease with increasing the frequency.At 10 and 100 Hz,one dielectric constant peak at 9.6℃ and one tanδ peak at 5.0℃ are observed at -120℃ to 180℃.展开更多
Helical 1,2-ethylene-silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like mesopores inside were prepared according to literature procedures. After carbonization, helical carbon/ silica nanofi...Helical 1,2-ethylene-silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like mesopores inside were prepared according to literature procedures. After carbonization, helical carbon/ silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like micropores inside were obtained. The morphologies and pore architectures of the carbon]silica nanofibers were characterized using transmission electron microscopy, field-emission scanning electron microscopy, powder X-ray diffraction and N2 sorptions. Although the mesopores inside shrank into micropores, the helical nanostructure remained. Moreover, several carbon/silica nanofibers with lamellar mesopores on the surfaces and concentric circular micropores inside were also obtained. After being calcined in air, helical silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like micropores inside were produced as well.展开更多
Single-handed helical phenolic resin nanofibers were synthesized through a supramolecular templating approach using the supramolecular self-assemblies of a pair of chiral low-molecular-weight amphiphiles as the templa...Single-handed helical phenolic resin nanofibers were synthesized through a supramolecular templating approach using the supramolecular self-assemblies of a pair of chiral low-molecular-weight amphiphiles as the templates and 2,4-dihydroxybenzoic acid and formaldehyde as the precursors.The phenolic resin nanofibers were characterized using field-emission scanning electron microscopy,transmission electron microscopy and diffused reflection circular dichroism.The results indicated that the chirality of the supramolecular self-assemblies was successfully transferred to the phenolic resin nanofibers.The left- and right-handed helical phenolic resin nanofibers exhibited opposite optical activity.展开更多
Left-handed, coiled, 4,4'-biphenylene bridged polybissilsesquioxane, tubular nanoribbons were prepared according to the published literature. After carbonization and removal of silica using HF aqueous solution, left-...Left-handed, coiled, 4,4'-biphenylene bridged polybissilsesquioxane, tubular nanoribbons were prepared according to the published literature. After carbonization and removal of silica using HF aqueous solution, left-handed, coiled, carbonaceous, tubular nanoribbons were obtained. The left- handed, coiled, carbonaceous, tubular nanoribbons were characterized using field-emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Raman spectropho- tometer, diffuse reflectance circular dichroism (DRCD), and N2 adsorptions. Micropores were formed due to the removal of silica. The nitrogen BET surface area is 1727 m2/g. A broad, positive DRCD signal, identified at 400-800 rim, indicates the carbonaceous, tubular nanoribbons exhibit optical activity. The helical pitch is proposed to play an important role in the position of the DRCD signal.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK2011354)the Priority Academic Program Development of Jiangsu High Education Institutions(PAPD)the National Natural Science Foundation of China(Nos.21071103 and 21074086)
文摘Single-handed helical silica nanotubes were prepared according to the literature procedures,using the self-assemblies of a pair of chiral cationic low-molecular-weight gelators as the templates.A chirality indicator,4,4'-bis(triethoxysilyl)-1,1'-biphenyl,was developed to determine the chirality of the silica nanotubes.The chirality of the surfaces and the bulky walls of the silica nanotubes were understood from the twist of the biphenylene rings.
基金supported by the Priority Academic Program Development of Jiangsu High Education Institutions(PAPD)
文摘Left and right-handed helical barium titanate nanotubes are prepared with the impregnation of Ba(OH)2 into single-handed helical titania nanotubes.Wide angle X-ray diffraction pattern and transmission electron microscopy image indicate that they are constructed by nanoparticles with a partially crystalline structure.The diffuse reflertance circular dichroism spectra indicate that they exhibit optical activity which was proposed to originate from chiral defects on the inner surfaces of the nanotubes.Both the dielectric constant and tanδ decrease with increasing the frequency.At 10 and 100 Hz,one dielectric constant peak at 9.6℃ and one tanδ peak at 5.0℃ are observed at -120℃ to 180℃.
基金supported by Natural Science Foundation of Jiangsu Province(No.BK2011354)the Priority Academic Program Development of Jiangsu High Education Institutions(PAPD)the National Natural Science Foundation of China(No.21104053, 21071103 and 21074086)
文摘Helical 1,2-ethylene-silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like mesopores inside were prepared according to literature procedures. After carbonization, helical carbon/ silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like micropores inside were obtained. The morphologies and pore architectures of the carbon]silica nanofibers were characterized using transmission electron microscopy, field-emission scanning electron microscopy, powder X-ray diffraction and N2 sorptions. Although the mesopores inside shrank into micropores, the helical nanostructure remained. Moreover, several carbon/silica nanofibers with lamellar mesopores on the surfaces and concentric circular micropores inside were also obtained. After being calcined in air, helical silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like micropores inside were produced as well.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK2011354)the Priority Academic Program Development of Jiangsu High Education Institutions(PAPD,No. YX10900114)the National Natural Science Foundation of China(No.21104053)
文摘Single-handed helical phenolic resin nanofibers were synthesized through a supramolecular templating approach using the supramolecular self-assemblies of a pair of chiral low-molecular-weight amphiphiles as the templates and 2,4-dihydroxybenzoic acid and formaldehyde as the precursors.The phenolic resin nanofibers were characterized using field-emission scanning electron microscopy,transmission electron microscopy and diffused reflection circular dichroism.The results indicated that the chirality of the supramolecular self-assemblies was successfully transferred to the phenolic resin nanofibers.The left- and right-handed helical phenolic resin nanofibers exhibited opposite optical activity.
基金supported by Natural Science Foundation of Jiangsu Province(No.BK2011354)the Priority Academic Program Development of Jiangsu High Education Institutions(PAPD)the National Natural Science Foundation of China(Nos.21104053, 21071103 and 21074086)
文摘Left-handed, coiled, 4,4'-biphenylene bridged polybissilsesquioxane, tubular nanoribbons were prepared according to the published literature. After carbonization and removal of silica using HF aqueous solution, left-handed, coiled, carbonaceous, tubular nanoribbons were obtained. The left- handed, coiled, carbonaceous, tubular nanoribbons were characterized using field-emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Raman spectropho- tometer, diffuse reflectance circular dichroism (DRCD), and N2 adsorptions. Micropores were formed due to the removal of silica. The nitrogen BET surface area is 1727 m2/g. A broad, positive DRCD signal, identified at 400-800 rim, indicates the carbonaceous, tubular nanoribbons exhibit optical activity. The helical pitch is proposed to play an important role in the position of the DRCD signal.