Anodic Growth of Large-Diameter Multipodal TiO2 Nanotubes

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• 作者：Arash Mohammadpour ; Prashant R. Waghmare ; Sushanta K. Mitra ; Karthik Shankar
• 刊名：ACS Nano
• 出版年：2010
• 出版时间：December 28, 2010
• 年：2010
• 卷：4
• 期：12
• 页码：7421-7430
• 全文大小：694K
• 年卷期：0
• ISSN：1936-086X

文摘

We report on the formation of a new class of nanostructures, namely, multipodal hollow titania nanotubes possessing two or more legs, achieved during the electrochemical anodization of titanium in diethylene glycol (DEG)-based electrolytes. The unique multipodal porous structure is expected to extend and enhance the applications of TiO₂ nanotube arrays. Multipodal nanotubes form by a process we term “nanotube combination”, which only occurs in viscous electrolytes at high anodization potentials in the presence of a low concentration of fluoride-bearing species. The mechanism of formation of multipodal nanotubes is considered, and the tube length at which nanotube combination occurs is predicted theoretically using a simplified analytical model. The results suggest that capillary forces strong enough to bend the TiO₂ nanotubes by tens of degrees are generated during the imbibition of electrolyte into and out of the intertubular spaces between adjacent tapered nanotubes.