Formation mechanism and packing options in tubular anodic titania films

Titania nanotube arrays were synthesized via anodic oxidation of titanium foils in glycerol electrolyte containing NH4F at anodization voltage ranging from 10 V to 30 V. The structural parameters of self-organized periodic arrays of titania nanotubes were determined by small-angle neutron scattering and scanning electron microscopy techniques. Transmission electron microscopy and electron diffraction studies of single-standing nanotubes revealed the presence of nanocrystalline titanium oxide phases with oxidation states lower than +4 (TiO, Ti2O3). Several assumptions on growth and self-organization mechanism of nanotube arrays have been made.