Hydrogel Based Anodization: A Novel Technique to Form Ordered Nano-sized Porous Oxide Layer on the Aluminum Surface

A hydrogel-based anodization system has been proposed, for the first time in the literature to our knowledge, to perform anodization. Here, the electrolyte solution is trapped inside the hydrogel, which makes the anodization process safer for the operators and environment. In addition, trapping the ions inside the hydrogel increases the reaction rate, and thus the process takes place in very short times. In the present study, the effects of the polymer concentration, process time, acid concentration and pressure were evaluated, and we found that the best porous structures with an average pore size of 26.7 nm were obtained for 4 M polymer concentration, 150 s process time, 410 kPa pressure and 10% (V/V) acid concentration. This study was preliminarily performed under hard anodization conditions, and in the future studies mild anodization conditions will be studied to be able to analyze the efficiency of this pioneering technique from all aspects.