Initial Self-Ordering of Porous Anodic Alumina: Transition from Polydispersity to Monodispersity

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• 作者：Myungjun Kim ; Hyunchul Kim ; Changdeuck Bae ; Joobong Lee ; Hyunjun Yoo ; Josep M. Montero Moreno ; Hyunjung Shin
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：November 20, 2014
• 年：2014
• 卷：118
• 期：46
• 页码：26789-26795
• 全文大小：382K
• ISSN：1932-7455

文摘

Self-ordered porous anodic alumina (PAA) membranes have been widely employed as a scaffold for fabricating various nanomaterials and functional nanostructures with an excellent uniformity. The self-organization processes are only found in narrow experimental windows even in PAA, and their formation mechanisms have not been fully understood yet and might allow us to access a hint that generally extends into other material systems. Here, we revisit the self-organization process of PAA by experimentally observing its initial stage in great detail. Surface morphologies of PAA were carefully monitored which have been imprinted upon the first anodization in the solutions of oxalic acid around the inflection point in the current鈥搕ime curves. The physical dimensions were analyzed by electron microscopy, and the degree of ordering was evaluated using the radial power spectral density method. We found that the inflection point reflects the occurrence of a uniform pore diameter as well as interpore distance which is crucial for the self-organization phenomena resulting from the minimization of surface free energy. The proposed model was further supported by electric field simulation near the inflection point.