INFLUENCE OF STERIC STABILIZERS ON THE ELECTROPOLYMERIZATION AND PROPERTIES OF POLYPYRROLES

Electropolymerization of pyrrole in aqueous solutions of sodium nitrate with additions of different steric stabilizers (e.g. polyvinylpyrrolidone, poly(vinyl alcohol), poly(ethylene oxide)) was conducted using potentiostatic, galvanostatic and potentiodynamic techniques. Different substrates (Pt, glassy carbon and stainless steel) were used. The electropolymerization processes were investigated and the resultant polymers were characterized in terms of morphology, adhesion and electroactivity. Thus, under galvanostatic conditions, the growth potential of the polymers was affected little by the presence of stabilizers. For potentiostatic and potentiodynamic methods, however, the presence of stabilizers reduced the rate of growth of the polymer. Furthermore, stabilizers were found to affect the morphology of the plate side and solution side of films. Adhesion to the substrate increased with increasing concentration of stabilizer until a maximum was attained, beyond which further additions of stabilizer began to reduce the adhesion. On some substrates, such as stainless steel, the presence of stabilizer improved the electroactivity of the deposited polymer.