Preparation of transparent anodic aluminum oxide films and their structural characteristics under thermal shock

Anodic aluminum oxide (AAO) films have a wide range of research and applications in the field of nanoscience and technology. Transparent AAO films require the oxide layer to be peeled off from the aluminum substrate to which it is attached, involving a complex preparation process and immersion in a variety of caustic solutions, resulting in the prepared AAO films that are very prone to fragmentation and unfavorable for applications. Here, we have prepared transparent AAO films by double-sided anodization method with secondary anodization, which consists of a double-sided porous structure spaced with a barrier layer. These transparent AAO films can be bent into bow shape and exhibit good toughness under the action of external forces applied at both ends. Then, the transparent AAO films were subjected to thermal shock experiments, and the changes in the microstructure of the AAO films before and after the thermal shock were analyzed. The relationship between the microstructure of the AAO films and the good toughness they exhibit was also investigated.