Function Calculation: A Simple Way to Predict the Geometry Parameters of Self-Organized Titania Nanotube Arrays

TNTAs were grown by anodization of titanium in mixed electrolytes consisting of water, ethylene-glycol and NH4F. With this electrolyte composition, the obtained nanotube layers show a high level of flexibility towards controllable tube geometries. We carefully investigated the internal relationship between the synthesis parameters and the resulting TNTA morphology, deriving a set of relations to link the preparation parameters with the geometric dimensions of the obtained TNTAs. We show that the nanotube outer diameter not only increases linearly with the applied anodization voltage, but also relates to the water content in the electrolyte, and that both the water content and fluoride content determines the kinetics of the tube growth. Thus, by adjusting the electrolyte composition and optimizing the anodization procedure, a wide range of pre-defined morphologies can be realized.