Preparation and characterization of polyaniline powder synthesized on microstructured aluminium

Aluminium surfaces were microstructured in 0.1 M HNO₃ by potentiodynamic anodic activation to potentials generating pitting. This surface was then used as an electrode to prepare polyaniline powder. The number of pits is responsible for the amount of powder produced. Emeraldine salt powder was successfully prepared from 0.4 M aniline in 0.5 M H₂SO₄ solution. Other acid solutions for deposition are not convenient because powders are electrochemically inactive (e.g., in 1 M HNO₃) or the electrode is covered by a film (e.g., in 0.5 M H₂C₂O₄).