Anodic formation of aligned and bamboo-type TiO2 nanotubes at constant low voltages

Bamboo-type TiO2 nanotubes with a highly ordered structure on titanium surface were synthesized by a self-assembly electrochemical anodization in viscous glycerol solution at constant low voltages. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) were used to characterize the structure and morphology of the bamboo-type TiO2 nanotubes. The experimental results show that the morphologies of the nanotubes are markedly influenced by the viscosity (the water content) of the electrolytes solution, the anodization voltage and the anodization time. Besides, a possible formation mechanism for the bamboo-type TiO2 nanotubes was proposed.