Three-dimensional structural engineering of nanoporous alumina by controlled sprinkling of an electrolyte on a porous anodic alumina (PAA) template

The significant effect of anodization current on the morphology of nanopores encourages us to consider a novel method for engineering these nanostructures. In this paper we study a controlled anodization process using controlled electrolyte stirring. This is done using an electrical pump with variable speed for sprinkling an electrolyte on a membrane. The variable voltage applied to the pump can control the temperature gradient and diffusion of the ions which produce the anodization current. Here we show the significant role of pumping and how this effect can be used in the engineering of nanopores as a three-dimensional nanostructure. These experiments are carried out for a variety of anodization voltages and various electrolyte concentrations, and thus we investigate how these parameters in the vicinity of pumping can control the porosity of the template in three dimensions.