High-Throughput Fabrication Process for Highly Ordered Through-Hole Porous Alumina Membranes Using Two-Layer Anodization

Alumina through-hole membranes with an ordered array of holes were obtained by the wet etching of two-layered anodic porous alumina, which was formed by the first anodization of Al in an acid solution under standard conditions and the subsequent anodization in concentrated H2SO4. In this process, the detachment of the porous alumina membrane and through-holing could be achieved simultaneously by etching in an appropriate acid solution. This is because the oxide layers formed in concentrated H2SO4 were more easily dissolved than the oxide layer formed in the standared acid solution. After the detachment of the membrane, the residual Al substrate could be repeatedly used for the preparation of ordered through-hole membranes. The obtained through-hole membranes are expected to be used in various applications. (C) 2015 Elsevier Ltd. All rights reserved.