Study on the kinetics of ferrocene derivatives in polymer electrolyte/electrode interface at microelectrode

Heterogeneous electron transfer rate constants (k(s)) and diffusion coeffic ients (D) of the ferrocene and its derivatives. in a new synthetic comb pol ymer solvent, poly(dimethylsiloxane-g-monomethylether polyethylene glycol) (SCP), and several other polymer solvents were estimated by using microelec trodes. Also, the influence of various supporting electrolytes on k(s) and D of ferrocene was studied. It was shown that k(s) and D of ferrocene decre ased with increasing anionic size of the supporting electrolyte, but k(s) t ended to increase with increasing radius of the solvated cation. Also, the cationic size of the supporting electrolytes had little effects on D. The v alues of k(s) and D for the ferrocene derivatives in the polymer solvents w ere in sharp contrast to those in monomeric solvents. Thus. the k(s) values were proportional to D in the polymer solvents. which indicates that solve nt dynamics control of the electrode reaction. The values of k(s) and D of ferrocene in SCP were larger than those in other polymer solvents indicatin g that SCP is a good polymer solvent. (C) 2000 Elsevier Science B.V. All ri ghts reserved.