Investigation of surface morphologies of TiO2 nanotube arrays by anodization in ethylene glycol electrolytes

This work describes the morphological-controlled growth of the TiO2 nanotube arrays by anodization of Ti foils in the ethylene glycol electrolytes containing 0.5 wt % NH4F and amount of water under a constant anodization voltage. FESEM was used to investigate the structure and morphology of the TiO2 nanotube arrays. It was found that the morphology is much different obtained in different electrolytes component by manipulating electrochemical conditions. The results of characterization indicate that the morphology with a bundled "nanograss" or nanowires appearance at the tube top depends on anodization voltage, electrolyte component and electrolyte viscosity. In addition, the formation details for these morphological features and the transformation relations among them were studied. In the present work, we demonstrate a simple approach how to prevent this effect.