A combined statistical and microscopic analysis of TiO2 nanotubes synthesized under different electrochemical anodizing conditions

In the present study, the electrochemical anodizing method was applied for the manufacturing of TiO2 nanotubes layers developed on pure titanium surfaces. Parameters such as voltage, anodizing time and type of electrolyte showed a considerable influence on both the TiO2 nanotubes diameters and their surface density distribution. The statistical distribution of nanotubes diameter was determined by means of both the Weibull and the Gaussian distribution analyses. Results showed that a not well organized nanotubes layer with not well defined shape was obtained when a simple aqueous 0.5% wt HF solution was used as electrolyte, while titania nanotubes formed when using an organic electrolyte under specific anodizing conditions were regularly shaped and uniformly distributed. It was also concluded that Weibull distribution fits better the experimental measurements, due to its ability to provide a reasonably accurate analysis with extremely small number of samples, and also to provide a simple and useful graphical plot of the data. The selection of electrochemical parameters applied for the synthesis of a nanolayer followed by its microscopic analysis along with the use of an appropriate statistical analysis of the diameters surface distribution constitutes tools which can be useful for designing and manufacturing nano-layers with specific characteristics.