Robust self-organization of oxide nanotubes over a wide pH range

A method of self-organization of TiO2 nanotube layers within a wide pH range from acidic to basic conditions using a NH4F/water/ glycerol electrolyte is described. The electrochemical conditions under which the nanotubes are self-organized, such as the anodization potential and time, and the composition and pH value of the electrolytes, have great influence on the growth behavior of the nanotubes. The method can be applied to other metals or metal alloys for the preparation of anodic nanotubes. An efficient growth of relatively long nanotubes can be achieved using an alkaline electrolyte with adjusted viscosity. Oxide nanotubes can also be prepared using basic conditions, which are more efficient for the self-organization of relatively long oxide nanotubes using an adjusted basic electrolyte.