Table of Contents
ISRN Nanotechnology
Volume 2011 (2011), Article ID 654730, 4 pages
http://dx.doi.org/10.5402/2011/654730
Research Article

Anisotropic Growth of Porous Anodic Alumina and Its Potential Application in Three-Dimensional Nanostructure Construction

Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Shandong Province, Qingdao 266100, China

Received 15 February 2011; Accepted 22 March 2011

Academic Editor: N. Tabet

Copyright © 2011 Jinhui Dai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The porous anodic alumina was fabricated by means of electrochemical oxidation using Al foil as a substrate in oxalic acid under constant anodic voltage at room temperature. Prior to anodization, the substrate surface with roughness in microscale was obtained through electrochemical treatment. The tube growth on the substrate was investigated using a scanning electron microscope (SEM). The results showed that the tube growth behavior of the porous anodic alumina was strongly dependent on the surface roughness. In presence of sphere-shaped cavities in microscale (diameter of 5~30 μm) on the surface of the substrate, the nanotubes were growing essentially away from the center of curvature of each cavity, forming individual growing regions separated by visible interface. The tube branching and tube cutoff were evidently observed in the growing regions and along the interface, respectively. Anisotropic growth of porous anodic alumina suggested its potential application in three-dimensional nanostructure construction.