Facile fabrication of free-standing TiO2 nanotube membranes with both ends open via self-detaching anodization

We report the first direct synthesis of free-standing TiO2 nanotube membranes based on self-detaching electrochemical anodization. The films with high-quality surfaces and both-side-open tubes could be obtained by appropriate thermal treatment during the process. The membranes are optically transparent after subsequent annealing to induce crystallization. The possible mechanism of the multi-step electrochemical process is also presented. This self-detaching process developed here is easy and efficient without additional chemical dissolution or etching and is shown to open new prospects for the application of TiO2 nanotubes in various fields. (C) 2010 Elsevier B.V. All rights reserved.