Nanofabrication of helical hybrid silica nanotubes using anionic gelators

A pair of anionic enantiomers, L-C12ValC10COONa and D-C12ValC10COONa, derived from valine was synthesized according to the literature. Helical hybrid silica nanotubes were prepared using these amphiphiles with 3-aminopropyltrimethoxysilane (APTMS) as a co-structure-directing agent and bis(silsesquioxane)s as the precursors. It was found that right- and left-handed helical nanotubes were obtained from L-C12ValC10COONa and D-C12ValC10COONa, respectively. CD spectra of the helical 4,4'-biphenylene-silica nanotubes indicated that the chirality of the organic self-assemblies were successfully transferred to the stacking of the aromatic rings. Moreover, single-handed helical 1,4-phenylene-silica, ethenylene-silica and methylene-silica nanotubes were also prepared. For ethylene-silica, both left- and right-handed helical nanotubes were identified by field-emission scanning electron microscopy.