The Porous Anode Of Titanium Oxide Nanotubes Preparation And Self Organization Process Of Research

This article emphasizes on the production of highly ordered porous anodic titania nanotube (PATNT) arrays under different experimental conditions. According to the SEM of PATNT and the voltage-time (V-t) curves and current-time (I-t) curves of the anodizing process, the mechanism of the formation and the self-ordering process of PATNT are discussed in detail.The self-ordering processes of PATNT were investigated in this paper. Many influence factors, such as, the pre-treatment technology of Ti substrate, anodizing time, electrolyte temperature, anodizing voltage and concentration of electrolytes, have been investigated in detail. The results indicate that the pre-treatment process of chemical polishing can make PATNT more regular and orderly. The length, diameter of the nanotubes and their orderliness will increase continuously with the anodizing time increases. There will be a thick layer of oxide on the surface of the nanotubes anodized below5℃. The length and diameter of the nanotubes will increase with the increase of the electrolyte temperature. But when the temperature is above60℃, the surface morphology of the nanotubes will be destroyed. The anodizing voltage and current density also affect the structure of PATNT. When the voltage is below80V, the diameter of the nanotubes will increase continuously with the increase of the voltage and current density. But the orderliness of PATNT will decrease when the voltage is below10V or above80V. The diameter of the nanotubes will also increase with the rise of the electrolyte concentration until it reaches lwt%. When electrolyte concentration is below0.1wt%, the ordered nanotubes will not emerge due to the low oxidation rate;when it’s above1wt%, the nanotubes will be damaged by the chemical corrosion.At last, highly ordered PATNT arrays with smooth walls are assembled by the second-step anodizing process. The pits left in the first anodizing process will guide the growth of the nanotubes in the second anodizing process. If the second anodizing voltage is lower than the first one, lotus-root-shape nanostructure will be obtained. The growing mechanism and the self-ordering process of the lotus-root-shape nanostructure in PATNT are proposed for the first time.