One Step Fabrication Of Ordered Nanoporous Alumia

A self-organizing porous material, Nanoporous Alumia (NPA) is an economical template for the fabrication of various nanomaterials.

This is due to its minute spaces and holes through which liquid and air may pass easily, without the need of the high-priced lithographic technique.

The characteristics of NPA (easily-controlled pore diameter, interpore distance and pore depth) form a befitting template for the synthesis of nanomaterials.

A well-ordered NPA can be employed through the fabrication of nanomaterials by template synthesis method, such as i) a two-step anodizing method and ii) pre-patterning method.

It is crucial to combine nanomaterials of uniform dimensions, as the properties of nanomaterials are significantly influenced by the dimensions.

However, the mentioned methods above are not feasible for large scale manufacturing due to the exorbitant cost and low throughput.

Hence, the objective of the study is to confirm on a simple method of oxide dissolution treatment to attain well-ordered NPA in shorter anodizing duration and higher temperature to enlarge the application on NPA in template synthesis of nanomaterials.

The study uses a single step anodizing at 50 V in 0.3 M oxalic acid at 15 degrees Celsius for 60 minutes, to produce NPA on aluminum surface.

By subjecting the nanoporous alumina to oxide dissolution treatment in a mixture of chromic acid and phosphoric acid, well-ordered pore and cell structure were obtained.

As a result, it was found that the oxide dissolution treatment improves the regularity of the cell and pore structure significantly and that this method is more convenient.

The post oxide dissolution treatment also exhibits ordered and nearly perfect hexagonal cell structure, a uniform closely honeycomb structure of NPA.

In addition, the pore diameters and the interpore distance are nearly uniform over the analyzed surface. Thus, the uniformity of the pore diameter and interpore distance are enhanced immensely.