Morphology of Polyaniline Films on the Surface of Al87Ni8Y5 Amorphous Metallic Alloy

Abstract

The morphology of polyaniline films, which were produced under the potentiodynamic conditions during 0.1 M aniline oxidation in the 0.5 M H₂SO₄ aqueous solutions on the different sides of Al₈₇Ni₈Y₅ amorphous metallic alloy electrode, has been studied on the initial stages of polymer formation. It was shown by scanning electron microscopy that thick granular film and thin smooth film forms on the contact and outer side of electrode respectively. Differences in the morphology of the polyaniline films on the different sides of electrode are conditioned by its amorphous nature, by the amorphous structure and thickness of oxide on the surface of working electrode and by stages of the initiation of aniline oxidation and growth of polymeric film. The character of the polyaniline films on the both electrode sides gives basis to assert that preferred 2D-growth of films takes place on the outer side of the Al₈₇Ni₈Y₅ electrode while the 3D-growth observes on the contact side on the initial stages of polymeric film formation. Aggregative micrograin structure of polyaniline confirms the nucleation of polymeric molecules in the delocalized or localized pittings in the oxide layer on the surface of amorphous electrode. The analysis of X-ray diffractogramms and electron diffraction spectra argues that the structure of polyaniline films on the contact side of electrode is an amorphous generally and polymer contains the products of the dissolution of both surface oxide film and amorphous metallic alloy.