Electrodeposition of Polyaniline Films bearing Sulfonic and Hydroxyl Groups Characterization and electrochemical stability

New copolymers having 2-anilinoethanol and N-sulfopropylaniline acid, as units in the main chain were prepared by cyclic voltammetry from 1M H2SO4 aqueous solution, and deposited on Pt and ITO electrodes using solutions containing different monomers ratios of 1:1, 1:2 and 2:1. The electropolymerization processes were carried out by sweeping the working electrode potential between 0.0 V and 1.3 V at 50 mVs(-1), for 20 cycles. The copolymers were deposited as green layers on working electrode surface. All copolymers exhibit electrochemical activity in H2SO4 solution but they became unstable starting with the second cycle. Among all synthesised copolymers, only PAnEtOH-AnPS-12 shows electrochemical activity in acetate buffer solution, pH 6.5. Raman spectra recorded for PAnEtOH and PAnEtOH-AnPS-21 revealed the presence of the characteristic bands for polyanilines in both oxidized and reduced form. SEM and AFM micrographs revealed that the copolymers layers present a smooth and compact morphology with small roughnesses. It was evidenced that the change of the electrolysis medium pH induces changes in the morphology of the copolymers layers. Copolymers having both aniline monomers were obtained from acetate buffer solutions at pH 4.5 and characterized.