Multilayered 1,2-ethylene-silica nanotubes were prepared with cetyltrimethylammonium bromide（CTAB） as a template and（S）-β-citronellol（CN） as a co-structure-directing agent.For a better understanding of the formation of this structure,the CN/CTAB molar ratio in the reaction mixtures was tuned.With increasing the CN/CTAB molar ratio,a hexagonal to lamellar phase trasformation was observed;and the morphologies of 1,2-ethylene-silica changed from rod to vesicle and then to tubular structure.CN droplets were proposed as the templates for the nanotubes.The obtained samples were characterized by means of X-ray diffraction,nitrogen sorption,field emission scanning electron microscopy and transmission electron microscopy.
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.
Helical mesoporous silica nanorods were prepared using cetyltrimethylammonium bromide and achiral alcohols as the co-structure-directing agents. They were characterized using field-emission scanning electron microscopy, transmission electron microscopy, nitrogen sorptions, and small angle X-ray diffraction. The length of the silica nanorods increases with increasing the length of the alcohols. When n-heptanol and n-octanol were used, helical mesoporous silica nanorods with lamellar mesopores on the surfaces were obtained.
Yun Yue PuYi LiWei ZhuangMing ZhangBao Zong LiYong Gang Yang
