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

Jinhui Dai,Zhibin Zhu,Xiang Huang,Xiaofei Qu,Pingwei Wu,Leiyan Shi,Jintao Tian

doi:10.5402/2011/654730

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.

Highlights

In recent years, there has been increasing interest in the fabrication of one-dimensional nanostructure materials because of their potential utilization in electronics, optics, and mechanics [1]
The diameter of the cavities was estimated to be in the range of 5∼ 30 μm, a result of surface roughness of the substrate in micro scale due to the electrochemical treatment
In the present study 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

Summary

Introduction

There has been increasing interest in the fabrication of one-dimensional nanostructure materials because of their potential utilization in electronics, optics, and mechanics [1]. Possessing higher pore density [4], uniform pore size, and high aspect ratio, the wellfabricated porous anodic alumina has been widely used as the template due to the remarkable hardness, thermal and anticorrupted stability together with the potentially low cost and relative simple preparation [5]. In such a case, Al foil with smooth surface after careful polishing was used as a substrate in general and multiple anodizing steps or even mechanical pretexturing [6, 7] were performed. The obtained results suggested a high possibility of preparing three-dimensional nanotemplate and as a result three-dimensional nanostructure

Methods

Results

Conclusion