Microstructure and shear fracture characteristics of porous anodic TiO2 layer before and after hot water treatment

► Water treatment of anodic TiO2 results in nano-sized and well-crystallized oxides. ► Before treatment, shear fracture occurs primarily within cavity-containing layer. ► After treatment, shear fracture occurs along bottom surface of nanostructured layer. ► After treatment, shear strength of anodic TiO2 layer decreases obviously.