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Fabrication of free‐standing TiO 2 nanotube membranes with through‐hole morphology
Author(s) -
Liao Jianjun,
Lin Shiwei,
Li Xiaogan,
Li Shipu,
Cao Xiankun,
Cao Yang
Publication year - 2012
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201100556
Subject(s) - membrane , materials science , layer (electronics) , etching (microfabrication) , nanotube , nanotechnology , anodizing , fabrication , morphology (biology) , substrate (aquarium) , chemical engineering , composite material , carbon nanotube , chemistry , aluminium , medicine , biochemistry , alternative medicine , oceanography , pathology , biology , geology , engineering , genetics
In the present work, we show a simple and robust ex‐situ method to fabricate free‐standing membranes consisting of vertically oriented, both‐side‐open TiO 2 nanotube arrays. In this method, self‐organized TiO 2 nanotube membranes with different thickness ranging from seven to tens of micrometers could be easily separated from the metallic Ti substrate by applying a reverse‐bias voltage at the end of anodization. The stress developing at the TiO 2 nanotubes/Ti interface during H 2 gas generation facilitates the separation of the TiO 2 membranes. This procedure leads to an intact, free‐standing TiO 2 nanotube membrane with closed bottoms. After exposing the TiO 2 membrane to HF vapor, the barrier layer at the closed bottoms was etched away, and then a free‐standing TiO 2 membrane with through‐hole morphology was obtained. The bottom‐opening process is a slow barrier layer thinning process. Meanwhile, it is found that the mean diameter of tube bottoms monotonously decreases with the increasing the etching time.