Design and Optimization of Anodic Aluminum Oxide Channels Through Anodization of Aluminum Foil

Abstract

TEM gold grids act as sensing chambers for liquid crystal based sensing applications, which are expensive. Anodized aluminum oxide (AAO) channels can replace these chambers and can help in performing multiple sensing on one substrate. In this research work, impure aluminum foil is used to study and optimize the AAO channels through anodization because of cost effectiveness and ease of fabrication. Stepwise anodization is performed by varying voltage and working temperature for nine set of experiments to increase the pore size of AAO channels. Anodization process was monitored to make current profiles that are a function of current and time to predict and analyze the mechanism of pores. The process of high voltage anodization produces local heat at the surface of aluminum foil which was reduced by maintaining low working temperatures of anodization bath and also with continuous stirring of electrolyte. Scanning electron microscopy was used to investigate surface morphology and cross sectional analysis of anodized aluminum oxide channels for each set of experiment. This research work resulted in formation of AAO channels with pore size ranging from 40-270 nm and length of 1-17 μm through optimized two-step anodization of impure aluminum foil performed in 5-vol % phosphoric acid at anodizing voltage of 40-190 V.