Surface characteristics and phase transformation of highly ordered TiO2 nanotubes

Highly ordered TiO₂ nanotubes with 85 μm length were fabricated by the electrochemical method for 17 h at 60 V in an ethylene glycol/0.5 % NH₄F/5 % water mixture solution. The nanotube arrangements and surface morphologies of the anodic titania films were clearly dependent on the electrolytes used in the fabrication process. The activation energy for the transformation from an amorphous to anatase structure was evaluated using differential scanning calorimetry (DSC) results and a Kissinger plot. The activation energy for anatase transformation on the anodic titania nanotubular film was estimated to be 208.9 kJ/mol.