Structural evolution of porous anodic alumina membrane by the influence of critical current density in H2SO4

Abstract

The surface morphology of self assembled porous alumina membrane was investigated as a function of applied voltage and bath temperature in H2SO4 electrolyte. The self order was improved with the increase in applied voltage with the critical impact of current density. Also, the enhancement of current density with increase in bath temperature was analysed. The resultant highly ordered porous alumina membrane was obtained at 25 V and 3 degC which exhibit a regular pore array of mean diameter of 35 nm and inter-pore distance of 65 nm. Below the self assembling voltage, higher the pore density caused, to form a poor uniformity/irregular film of growth. However, anodization at higher bath temperature enhanced the surface defects and induced the arbitrary etching of pore edges. FESEM and 2-D FFT images were used to perform the characteristics of the alumina membrane