Sol-gel transcription of semi-fluorinated organogel fiber into fluorocarbon-functionalized silica nanotubes

The synthesis of silica nanotubes using the fibrous structure formed by a perfluoroalkyl chain-containing organogelator as a template has been demonstrated. The gelator 1 was dissolved in hot ethanol, and then tetraethoxysilane (TEOS), F8-TEOS, propylamine, and water were added to the hot solution. Aggregation of perfluoroalkyl chains between the gelator and the functionalized alkoxysilanes was a primary factor for achieving the transcription of the fibrous structure into the tubular product. The sol-gel condensation using trialkoxysilanes possessing a long alkyl chain instead of the perfluoroalkyl chain was also performed. The addition of C12-TEOS or C-18-TEOS resulted in the formation of granular silica particles, indicating that alkyl chains in the alkoxysilanes are not effective for forming a tubular structure. The proposed approach to form silica nanotubes presents possibilities to fabricate a broad range of nanostructured materials.