Chronoamperometric and morphological investigation of nucleation and growth mechanism of poly(azure A) thin films

Nucleation and growth analysis of formation of poly(azure A) thin films was carried out in this study. Electropolymerization of AA was achieved by using potentiodynamic (cyclic voltammetry) and potentiostatic (constant potential) techniques. Nucleation and growth mechanism of poly(AA) was determined by fitting the potentiostatic current density–time (j–t) transients to theoretical nucleation model. Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) were performed to confirm the j–t transient results. Optical characterization was carried out by using UV–vis. absorption spectroscopy. Cyclic voltammetry experiments show that oxide formation of gold working electrode takes place at higher potentials than 900 mV besides electropolymerization of AA. Potentiostatic j–t transient and morphology studies reveal that nucleation and growth mechanism of poly(AA) film follows consecutive two instantaneous 3-D mechanisms besides random adsorption resulting in two different structures. UV–vis. absorption studies indicate that AA monomer exhibit a main band which broadens and shifts to shorter wavelength values and an additional band arises at 335 nm after the electropolymerization process.