Dispersion of crystallites of the metal substrate during the electropolymerization of 2-hydroxy-3-aminophenazine (HAPh) on Au: Effect of Au crystallites on the kinetics and mechanism of charge-transfer reactions between the polymer and redox species in electrolyte

The electrochemical polymerization of 2-hydroxy-3-aminophenazine (HAPh) has been studied in aqueous perchloric acid solutions. Under potential cycling the polymerization reaction is accompanied by electrodissolution/electrodeposition of the An substrate onto which the polymer is deposited. TEM observations have revealed two kinds of crystalline grains in the pHAPh polymer film. The first kind consists of spherical grains of pure gold which are randomly oriented in the polymer matrix. The second kind consists of oriented well-shaped crystals of unknown composition, but most probably crystals of an intermediate Au(III) complex. The dispersed Au crystallites affect the kinetics and mechanism of charge-transfer reactions between the polymer and redox species in electrolyte, such as dihydroxybenzenes and hydrazine, as well as their permeability and incorporation into the polymer film.