Chiral colloids: homogeneous suspension of individualized SiO2 helical and twisted nanoribbons.

Finely tuned chiral nanometric silica fibers were synthesized based on sol-gel chemistry using organic self-assembly as a template. The optimization of the sol-gel process in acidic conditions allowed us to reduce the transcription time by a factor of 10. These nanohelices were successfully fragmented while preserving the fine internal structures from several micrometers to several hundreds of nanometers in length by a sonication method previously reported for carbon nanotubes. By carefully choosing the nature of the solvent, the sonication power, pH in the case of water, and densification of the silica walls by freeze-drying, the homogeneous and stable colloidal suspensions of individualized chiral nanometric silica ribbons with controlled length were obtained.