Zhengping Xi

Highly Ordered Coaxial Bimodal Nanotube Arrays Prepared by Self-Organizing Anodization on Ti Alloy†

The fabrication of nanomaterials with well-ordered complex structures is one of the most important issues among advanced materials sciences, not only due to their potential applications, such as information-storage devices, microelectronics, and biosensors, but also due to their high technological impact. Electrochemical self-organization is an efficient approach towards building microblocks and nanoblocks into highly ordered macroscopic materials, which can be observed in deposition or dissolution reactions. In the past few years, highly ordered, vertically oriented tubular or porous nanostructures have been fabricated by simple anodization on Si, Al, Ti, and some other alloys. A method that provides control of the architecture of titania nanotube arrays is particularly desirable because, when such arrays are highly ordered, they possess many interesting properties. To date, the microstructure, diameter, and length of such oxide nanotubes in highly ordered arrays has been controlled by varying anodization parameters including the applied potential, concentration, pH value of electrolytes, anodization time, and suitable co-operation of alloying elements. TiO2 nanotube arrays have been the subject of extensive investigations to realize heteroatomic nanotubes, for example, Ti Nb O, Ti Al O, and Ti Fe O nanotube arrays. In the past few decades, progress has been made in fabricating coaxial nanotubular structures by filling the hollow cavities of nanotubes with nanorods, which may be shielded