Electrochemistry for redox polymer film of N,N′-bis(3-pyrrol-1-yl-propyl)-4,4′-bipyridinium ion

The monomer N,N'-bis(3-pyrrol-1-yl-propyl)-4,4'-bipyridinium (PF6)(2) was electrochemically polymerized on glassy carbon electrode surface. This polymer film electrode has electroactive sites on its bipyridinium ions distributed at the polymer strands. The formal potentials of the electrodes were -0.41V and -0.81V(vs. SSCE) for each step at phosphate buffer (pH=5.70). The diffusion coefficients of the dopants ions into the polymer matrix were 1.57 x 10(-4) and 4.35 x 10(-5) cm(2)s(-1) for first and second redox couple, respectively. The rate constants of electron transfer at V2+/+ of the first step was a 57.53 s-1, which was 22 times higher than V+/0 one having 2.63 s(-1) in the solution. The charge transfer resistance of the polymer film was influenced by the dopant ion of the electrolyte. Thus the resistances were 22.63, 16.81, 12.44 and 11.36 k Ohm for LiClO4, NaClO4, KClO4, and phosphate buffer, respectively. The reaction order of the electropolymerization was first order and the rate constant of the polymerization was 1.31x10(-1) s(-1) as determined by EQCM method. The G.C./p-BPB type electrode doped with phosphate ions showed a stability and reproducibility in CV procedure over 20 cycles.