ELECTROCHEMICAL PROPERTIES OF POLY[3-(OMEGA-4-PYRIDYLALKYL)THIOPHENES]

Poly[3-(omega-4-pyridylalkyl)thiophenes] (P(P(n)T); n = 2, 5, 7, 9, 11 ) were prepared on the surfaces of Pt disk electrodes by oxidative ele ctropolymerization of the respective monomers. Scanning electron micro scopy and cyclic voltammetry were used to investigate the surface stru cture and electrochemical properties of the polymer-modified electrode s. Apparent diffusion coefficients D-app for charge transfer in the po lymer matrices were measured by chronoamperometry, and revealed a depe ndency on both the porous structure of the polymers (which is determin ed by the length of the alkyl chains between thiophene and pyridyl gro ups), and the nature of the supporting electrolytes. A.c. impedance sp ectra depended on the doped state of the films and the nature of the s upporting electrolytes. In oxidized polymers, the charge transfer proc esses within the bulk polymers and at interfaces are controlled by bot h kinetic factors and diffusion, while for the reduced films kinetic f actors predominate.