A sandwich porous anodic alumina (PAA/Al2O3/PAA) film was successfully designed and fabricated using the customary two-step anodization approach on both sides of an aluminum foil. The structure of the film was determined with field emission scanning electron microscopy (SEM). The SEM shows the PAA membranes has a well-defined nanostructure. All nanoholes stand symmetrically on both sides of the barrier layer. The average pore diameter reaches 40 nm.
porous alumina membrane; anodization; template
