The formation of helical mesoporous silica nanotubes

Abstract

Three chiral cationic gelators were synthesized. They can form translucent hydrogels in pure water. These hydrogels become highly viscous liquids under strong stirring. Mesoporous silica nanotubes with coiled pore channels in the walls were prepared using the self-assemblies of these gelators as templates. The mechanism of the formation of this hierarchical nanostructure was studied using transmission electron microscopy at different reaction times. The results indicated that there are some interactions between the silica source and the gelator. The morphologies of the self-assemblies of gelators changed gradually during the sol-gel transcription process. It seems that the silica source directed the organic self-assemblies into helical nanostructures.

Preparation of helical titania nanotubes using a sol–gel transcription approach

“…We reported previously that single-handed helical mesoporous silica and organic-inorganic hybrid silica nanostructures could be prepared using the self-assembly of chiral lowmolecular-weight amphiphiles to create templates in water [16][17][18]. The interactions between the silica or organicinorganic silica oligomers and the chiral low-molecular-weight amphiphiles play an important role in controlling the morphologies and pore architectures of the final products.…”

“…A sol-gel transcription approach was developed for the preparation of chiral nanotubes [10][11][12]; over the last decade, both single-handed helical silica [10][11][12] and organic-inorganic hybrid silica nanotubes [13,14] have been prepared using this method. A modified version of this technique was used to prepare varieties of single-handed helical mesoporous silica and polysilsesquioxane nanostructures [15][16][17][18]. Although titania nanotubes can also be prepared using the sol-gel transcription approach [19][20][21][22][23][24], only a few nanotubes will exhibit a helical morphology [23,24]; in these cases, the selfassembled structures of cholesterol [24] and 1,2-diaminocyclohexane derivates [23] acted as templates.…”

A Better Understanding of the Formation of Silica Nanococoons

“…The π-π stacking of the aromatic rings was identified in the CD spectrum at gel state. 21 It can also form organogels in tetrachloride carbon, tetrahydrofuran, toluene, chlorobenezene and nitrobenzene. Left-handed helical nanotubes with chiral pore channels in the walls can be prepared using the self-assemblies of L-18Phe6PyBr as templates at the concentration of 10.0 mg•mL -1 .…”

“…Left-handed helical nanotubes with chiral pore channels in the walls can be prepared using the self-assemblies of L-18Phe6PyBr as templates at the concentration of 10.0 mg•mL -1 . 21 Herein, a sol-gel reaction was carried out at the concentration of 2.0 mg•mL -1 . Natural biomineralization creates a variety of organic-inorganic hybrid porous structures, such as bones, teeth, and diatom cell walls.…”

Formation of Left‐handed Double Twisted Silica Nanoribbons

“…It has been reported previously that left-handed coiled nanotubes, each of which was constructed by two nanoribbons, could be prepared using L-18Val6PyBr and L-18Val11PyBr. 14,26 The chirality of the chiral centers of the amphiphiles plays an important role in controlling the handedness of the final products. Namely, the chirality of the amphiphiles was transferred to the organic self-assemblies and then to the silicas.…”